diff --git a/.github/scripts/contrib.sh b/.github/scripts/contrib.sh
index 0bcf6153e..46da0954e 100755
--- a/.github/scripts/contrib.sh
+++ b/.github/scripts/contrib.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
 
 antispam=", at the domain "
 
diff --git a/.github/scripts/trailing-newlines.sh b/.github/scripts/trailing-newlines.sh
index 5e4c7e8e5..ff8c71dfe 100755
--- a/.github/scripts/trailing-newlines.sh
+++ b/.github/scripts/trailing-newlines.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
 
 # Checking version to force it fail the build if rg is not installed.
 # Because `set -e` does not work inside the subshell $()
diff --git a/.github/workflows/checks.yml b/.github/workflows/checks.yml
index 28c02e04c..cf8e02be1 100644
--- a/.github/workflows/checks.yml
+++ b/.github/workflows/checks.yml
@@ -3,27 +3,239 @@ name: Checks
 on: [push, pull_request]
 
 jobs:
-  test:
-    runs-on: ubuntu-latest
+  tests:
+    name: ${{ matrix.os }} ${{ matrix.BUILD_TYPE }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ ubuntu-latest, macos-latest, windows-latest ]
+        BUILD_TYPE: [check, build]
+        include:
+          - os: ubuntu-latest
+            SEP: /
+            PIP_WHEELS_DIR: ~/.cache/pip
+            CARGO_INDEX_DIR: ~/.cargo/git
+            CARGO_REGISTRY_DIR: ~/.cargo/registry
+            ANKI_PYTHON_WHEELS: anki_linux_python_wheels
+
+          - os: macos-latest
+            SEP: /
+            PIP_WHEELS_DIR: ~/Library/Caches/pip
+            CARGO_INDEX_DIR: ~/.cargo/git
+            CARGO_REGISTRY_DIR: ~/.cargo/registry
+            ANKI_PYTHON_WHEELS: anki_macos_python_wheels
+
+          - os: windows-latest
+            SEP: \
+            PIP_WHEELS_DIR: ~\AppData\Local\pip\Cache
+            CARGO_INDEX_DIR: C:\Rust\.cargo\git
+            CARGO_REGISTRY_DIR: C:\Rust\.cargo\registry
+            ANKI_PYTHON_WHEELS: anki_windows_python_wheels
+
+      # Keep running all matrices if something fail
+      fail-fast: false
+
     steps:
+      - run: git config --global core.autocrlf false
+        if: matrix.os == 'windows-latest'
+
       - uses: actions/checkout@v2
+
+      - name: Configure Linux environment variables
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          # echo "::set-env name=SHELLFLAGS::-x"
+          echo "::set-env name=BUILDFLAGS::"
+          echo "::set-env name=RSPY_TARGET_DIR::${GITHUB_WORKSPACE}/target"
+          echo "::set-env name=CARGO_TARGET_DIR::${GITHUB_WORKSPACE}/target"
+
+      - name: Configure Mac OS environment variables
+        if: matrix.os == 'macos-latest'
+        run: |
+          # echo "::set-env name=SHELLFLAGS::-x"
+          echo "::set-env name=BUILDFLAGS::"
+
+          # Disabled for Mac OS because it was not reusing the cached files
+          # https://github.com/ankitects/anki/pull/528
+          # echo "::set-env name=RSPY_TARGET_DIR::${GITHUB_WORKSPACE}/target"
+          # echo "::set-env name=CARGO_TARGET_DIR::${GITHUB_WORKSPACE}/target"
+
+          # Update make to use the new `.SHELLFLAGS` feature
+          # https://stackoverflow.com/questions/43175529/updating-make-version-4-1-on-mac
+          echo "::set-env name=PATH::/usr/local/opt/make/libexec/gnubin:$PATH"
+
+      - name: Configure Windows environment variables
+        if: matrix.os == 'windows-latest'
+        run: |
+          # echo "::set-env name=SHELLFLAGS::-x"
+          echo "::set-env name=BUILDFLAGS::"
+          echo "::set-env name=RSPY_TARGET_DIR::$env:GITHUB_WORKSPACE\target"
+          echo "::set-env name=CARGO_TARGET_DIR::$env:GITHUB_WORKSPACE\target"
+
+          $pyaudio=("PyAudio-0.2.11-cp37-cp37m-win_amd64.whl")
+          $new_path=("$env:GITHUB_WORKSPACE;$env:PATH")
+          $new_path=("$env:GITHUB_WORKSPACE\shims;$new_path")
+
+          echo "::set-env name=pacmanbin::pacman-5.1.1-3-x86_64.pkg.tar.xz"
+          echo "::set-env name=pacmanmirror::pacman-mirrors-20200307-1-any.pkg.tar.xz"
+          echo "::set-env name=pacmankeys::msys2-keyring-r9.397a52e-1-any.pkg.tar.xz"
+          echo "::set-env name=pyaudio::$pyaudio"
+          echo "::set-env name=PATH::$new_path"
+          echo "::set-env name=RUST_BACKTRACE::full"
+          echo "::set-env name=SCOOP::$env:GITHUB_WORKSPACE"
+          echo "::set-env name=SCOOP_GLOBAL::$env:GITHUB_WORKSPACE"
+          echo "::set-env name=ANKI_EXTRA_PIP::python -m pip install $pyaudio"
+
+      # Necessary for now for the cargo cache:
+      # https://github.com/actions/cache/issues/133#issuecomment-599102035
+      - name: Fix ~/.cache permissions
+        if: matrix.os == 'ubuntu-latest' || matrix.os == 'macos-latest'
+        run: |
+          sudo chown -R $(whoami):$(id -ng) ~/.cargo/
+
+      - name: Cache pyenv
+        uses: actions/cache@v1
+        with:
+          path: ${{ github.workspace }}${{ matrix.SEP }}pyenv
+          key: ${{ runner.os }}-pyenv-${{ hashFiles('**/Makefile') }}-${{ hashFiles('**/requirements.txt') }}-14-
+
+      # Disabling these caches for now because they do not seem to be used/help
+      # https://github.com/ankitects/anki/pull/528
+      # - name: Cache pip wheels
+      #   uses: actions/cache@v1
+      #   with:
+      #     path: ${{ matrix.PIP_WHEELS_DIR }}
+      #     key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}-14-
+
+      - name: Cache cargo index
+        uses: actions/cache@v1
+        with:
+          path: ${{ matrix.CARGO_INDEX_DIR }}
+          key: ${{ runner.os }}-cargo-index-${{ hashFiles('**/Cargo.toml') }}-14-
+
+      - name: Cache cargo registry
+        uses: actions/cache@v1
+        with:
+          path: ${{ matrix.CARGO_REGISTRY_DIR }}
+          key: ${{ runner.os }}-cargo-registry-${{ hashFiles('**/Cargo.toml') }}-14-
+
+      - name: Cache cargo target
+        uses: actions/cache@v1
+        with:
+          path: ${{ github.workspace }}${{ matrix.SEP }}target
+          key: ${{ runner.os }}-cargo-target-${{ hashFiles('**/Cargo.toml') }}-${{ matrix.BUILD_TYPE }}-14-
+
+      - name: Cache cargo rslib
+        uses: actions/cache@v1
+        with:
+          path: ${{ github.workspace }}${{ matrix.SEP }}rslib${{ matrix.SEP }}target
+          key: ${{ runner.os }}-cargo-rslib-${{ hashFiles('**/Cargo.toml') }}-${{ matrix.BUILD_TYPE }}-14-
+
+      - name: Cache cargo rspy
+        uses: actions/cache@v1
+        with:
+          path: ${{ github.workspace }}${{ matrix.SEP }}rspy${{ matrix.SEP }}target
+          key: ${{ runner.os }}-cargo-rspy-${{ hashFiles('**/Cargo.toml') }}-${{ matrix.BUILD_TYPE }}-14-
+
+      - name: Cache pacman
+        if: matrix.os == 'windows-latest'
+        uses: actions/cache@v1
+        id: cache-pacman
+        with:
+          path: C:\Program Files\Git
+          key: ${{ runner.os }}-pacman-${{ hashFiles('**/checks.yml') }}-14-
+
+      - name: Set up pacman, rsync
+        if: matrix.os == 'windows-latest' && steps.cache-pacman.outputs.cache-hit != 'true'
+        shell: cmd
+        run: |
+          echo on
+          curl -LO http://repo.msys2.org/msys/x86_64/%pacmanbin%
+          curl -LO http://repo.msys2.org/msys/x86_64/%pacmanmirror%
+          curl -LO http://repo.msys2.org/msys/x86_64/%pacmankeys%
+
+          :: https://stackoverflow.com/questions/1359793/programmatically-extract-tar-gz
+          7z x "%pacmanbin%" -so | 7z x -aoa -si -ttar -o"%programfiles%\Git"
+          7z x "%pacmanmirror%" -so | 7z x -aoa -si -ttar -o"%programfiles%\Git"
+          7z x "%pacmankeys%" -so | 7z x -aoa -si -ttar -o"%programfiles%\Git"
+
+          :: Manually Install Pacman Binaries
+          :: https://github.com/Alexpux/MSYS2-pacman/issues/50
+          set "PATH=%programfiles%\Git\usr\bin"
+          bash pacman-key --init
+          bash pacman-key --populate msys2
+          bash pacman-key --refresh-keys
+          pacman -Tv
+          pacman -Syyuuv --overwrite='*'
+          pacman -Syuuv --overwrite='*'
+          pacman --version
+
+          :: We must install bash first, otherwise we will have bash fork errors:
+          :: https://github.com/evandroforks/anki/runs/524857054?check_suite_focus=true
+          :: 0 [main] pacman 748 dofork: child -1 - forked process 2896 died unexpectedly
+          pacman -Sv --noconfirm --overwrite='*' bash
+          pacman -Sv --noconfirm --overwrite='*' rsync
+
+          :: clean all packages to decrease image size
+          pacman -Sccv --noconfirm
+          pacman -Qsv --noconfirm
+
+      - name: Set up curl pyaudio, rename
+        if: matrix.os == 'windows-latest'
+        shell: cmd
+        run: |
+          echo on
+          curl -LO https://download.lfd.uci.edu/pythonlibs/s2jqpv5t/%pyaudio%
+          curl -LO https://raw.githubusercontent.com/subogero/rename/master/rename
+
+      - name: Set up Windows scoop, gettext, ripgrep
+        if: matrix.os == 'windows-latest'
+        shell: cmd
+        run: |
+          echo on
+          powershell -executionpolicy bypass "& Invoke-Expression (New-Object System.Net.WebClient).DownloadString('https://get.scoop.sh')"
+          scoop install -g gettext ripgrep
+
+      - name: Set up Ubuntu ripgrep, pyaudio, gettext, rename
+        if: matrix.os == 'ubuntu-latest'
+        run: |
+          sudo apt update
+          sudo apt install portaudio19-dev gettext rename
+          sudo snap install ripgrep --classic
+
+      - name: Set up brew ripgrep, pyaudio, gettext, rename
+        if: matrix.os == 'macos-latest'
+        run: |
+          brew install portaudio protobuf gettext rename ripgrep make
+          brew link gettext --force
+
       - name: Set up python
         uses: actions/setup-python@v1
         with:
           python-version: 3.7
+
       - name: Set up protoc
         uses: ankitects/setup-protoc@master
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
+
       - name: Set up node
         uses: actions/setup-node@v1
         with:
           node-version: 12
-      - name: Run checks
-        run: |
-          # add requirements
-          sudo apt update; sudo apt install portaudio19-dev gettext rename
-          sudo snap install ripgrep --classic
-          export CARGO_TARGET_DIR=~/target
-          export RSPY_TARGET_DIR=~/target
-          make check build BUILDFLAGS=""
+
+      - run: make develop
+        if: matrix.BUILD_TYPE != 'check'
+
+      - run: make build
+        if: matrix.BUILD_TYPE != 'check'
+
+      - run: make check
+        if: matrix.BUILD_TYPE == 'check'
+
+      - name: Upload python wheels
+        if: matrix.BUILD_TYPE != 'check'
+        uses: actions/upload-artifact@v1
+        with:
+          name: ${{ matrix.ANKI_PYTHON_WHEELS }}
+          path: dist
diff --git a/.gitignore b/.gitignore
index 7e4935ee6..57ab44f16 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@
 .build
 .coverage
 .DS_Store
+rename
 dist
 pyenv
 .mypy_cache
diff --git a/Makefile b/Makefile
index 5ade34310..c6fddd168 100644
--- a/Makefile
+++ b/Makefile
@@ -1,10 +1,23 @@
 SHELL := /bin/bash
 
+ifndef SHELLFLAGS
+	SHELLFLAGS :=
+endif
+
+.SHELLFLAGS := -eu -o pipefail ${SHELLFLAGS} -c
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+
 ifndef OS
 	OS := unknown
 endif
 
 ifeq (${OS},Windows_NT)
+	# Windows terminal is confusing it with its `cmd` builtin `rename` command
+	ifndef RENAME_BIN
+		RENAME_BIN := perl rename
+	endif
+
 	ifndef ACTIVATE_SCRIPT
 		ACTIVATE_SCRIPT := pyenv/Scripts/activate
 	endif
@@ -13,6 +26,10 @@ ifeq (${OS},Windows_NT)
 		PYTHON_BIN := python
 	endif
 else
+	ifndef RENAME_BIN
+		RENAME_BIN := rename
+	endif
+
 	ifndef ACTIVATE_SCRIPT
 		ACTIVATE_SCRIPT := pyenv/bin/activate
 	endif
@@ -26,10 +43,7 @@ ifndef ANKI_EXTRA_PIP
 	ANKI_EXTRA_PIP := true
 endif
 
-.SHELLFLAGS := -eu -o pipefail -c
 .DELETE_ON_ERROR:
-MAKEFLAGS += --warn-undefined-variables
-MAKEFLAGS += --no-builtin-rules
 SUBMAKE := $(MAKE) --print-directory
 .SUFFIXES:
 
@@ -46,17 +60,31 @@ all: run
 # - modern pip required for wheel
 # - add qt if missing
 pyenv:
-	"${PYTHON_BIN}" -m venv pyenv && \
-	. "${ACTIVATE_SCRIPT}" && \
-	python --version && \
-	python -m pip install --upgrade pip setuptools && \
-	${ANKI_EXTRA_PIP} && \
-	python -c 'import PyQt5' 2>/dev/null || python -m pip install -r qt/requirements.qt
+	# https://github.com/PyO3/maturin/issues/283
+	# Expected `python` to be a python interpreter inside a virtualenv
+	set -eu -o pipefail ${SHELLFLAGS}; \
+	"${PYTHON_BIN}" -m pip install virtualenv; \
+	"${PYTHON_BIN}" -m venv pyenv; \
+	case "$$(uname -s)" in CYGWIN*|MINGW*|MSYS*) \
+		dos2unix "${ACTIVATE_SCRIPT}"; \
+		VIRTUAL_ENV="$$(pwd)"; \
+		VIRTUAL_ENV="$$(cygpath -m "$${VIRTUAL_ENV}")"; \
+		sed -i -- "s@VIRTUAL_ENV=\".*\"@VIRTUAL_ENV=\"$$(pwd)/pyenv\"@g" "${ACTIVATE_SCRIPT}"; \
+		sed -i -- "s@export PATH@export PATH; VIRTUAL_ENV=\"$${VIRTUAL_ENV}/pyenv\";@g" "${ACTIVATE_SCRIPT}"; \
+		;; esac; \
+	. "${ACTIVATE_SCRIPT}"; \
+	python --version; \
+	python -m pip install --upgrade pip setuptools; \
+	${ANKI_EXTRA_PIP}; \
+	if ! python -c 'import PyQt5' 2>/dev/null; then \
+		python -m pip install -r qt/requirements.qt; \
+	fi;
 
 # update build hash
 .PHONY: buildhash
 buildhash:
-	@oldhash=$$(test -f meta/buildhash && cat meta/buildhash || true); \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	oldhash=$$(test -f meta/buildhash && cat meta/buildhash || true); \
 	newhash=$$(git rev-parse --short=8 HEAD || echo dev); \
 	if [ "$$oldhash" != "$$newhash" ]; then \
 		echo $$newhash > meta/buildhash; \
@@ -64,16 +92,16 @@ buildhash:
 
 .PHONY: develop
 develop: pyenv buildhash prepare
-	@set -eo pipefail && \
-	. "${ACTIVATE_SCRIPT}" && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	. "${ACTIVATE_SCRIPT}"; \
 	for dir in $(DEVEL); do \
 		$(SUBMAKE) -C $$dir develop DEVFLAGS="$(DEVFLAGS)"; \
 	done
 
 .PHONY: run
 run: develop
-	@set -eo pipefail && \
-	. "${ACTIVATE_SCRIPT}" && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	. "${ACTIVATE_SCRIPT}"; \
 	echo "Starting Anki..."; \
 	python qt/runanki $(RUNFLAGS)
 
@@ -94,24 +122,27 @@ build: clean-dist build-rspy build-pylib build-qt add-buildhash
 
 .PHONY: build-rspy
 build-rspy: pyenv buildhash
-	@. "${ACTIVATE_SCRIPT}" && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	. "${ACTIVATE_SCRIPT}"; \
 	$(SUBMAKE) -C rspy build BUILDFLAGS="$(BUILDFLAGS)"
 
 .PHONY: build-pylib
 build-pylib:
-	@. "${ACTIVATE_SCRIPT}" && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	. "${ACTIVATE_SCRIPT}"; \
 	$(SUBMAKE) -C pylib build
 
 .PHONY: build-qt
 build-qt:
-	@. "${ACTIVATE_SCRIPT}" && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	. "${ACTIVATE_SCRIPT}"; \
 	$(SUBMAKE) -C qt build
 
 .PHONY: clean
 clean: clean-dist
-	@set -eo pipefail && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
 	for dir in $(DEVEL); do \
-	  $(SUBMAKE) -C $$dir clean; \
+		$(SUBMAKE) -C $$dir clean; \
 	done
 
 .PHONY: clean-dist
@@ -120,33 +151,37 @@ clean-dist:
 
 .PHONY: check
 check: pyenv buildhash prepare
-	@set -eo pipefail && \
-	.github/scripts/trailing-newlines.sh && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	.github/scripts/trailing-newlines.sh; \
 	for dir in $(CHECKABLE_RS); do \
-	  $(SUBMAKE) -C $$dir check; \
-	done && \
-	. "${ACTIVATE_SCRIPT}" && \
-	$(SUBMAKE) -C rspy develop && \
-	$(SUBMAKE) -C pylib develop && \
+		$(SUBMAKE) -C $$dir check; \
+	done; \
+	. "${ACTIVATE_SCRIPT}"; \
+	$(SUBMAKE) -C rspy develop; \
+	$(SUBMAKE) -C pylib develop; \
 	for dir in $(CHECKABLE_PY); do \
-	  $(SUBMAKE) -C $$dir check; \
+		$(SUBMAKE) -C $$dir check; \
 	done;
 	@echo
 	@echo "All checks passed!"
 
 .PHONY: fix
 fix:
-	@set -eo pipefail && \
-	. "${ACTIVATE_SCRIPT}" && \
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	. "${ACTIVATE_SCRIPT}"; \
 	for dir in $(CHECKABLE_RS) $(CHECKABLE_PY); do \
-	  $(SUBMAKE) -C $$dir fix; \
+		$(SUBMAKE) -C $$dir fix; \
 	done; \
 
 .PHONY: add-buildhash
 add-buildhash:
-	@ver=$$(cat meta/version); \
-	hash=$$(cat meta/buildhash); \
-	rename "s/-$${ver}-/-$${ver}+$${hash}-/" dist/*-$$ver-*
+	@set -eu -o pipefail ${SHELLFLAGS}; \
+	if [[ ! -f rename ]]; then \
+		curl --silent -LO https://raw.githubusercontent.com/subogero/rename/master/rename; \
+	fi; \
+	ver="$$(cat meta/version)"; \
+	hash="$$(cat meta/buildhash)"; \
+	${RENAME_BIN} "s/-$${ver}-/-$${ver}+$${hash}-/" dist/*-"$${ver}"-*
 
 
 .PHONY: pull-i18n
diff --git a/README.contributing b/README.contributing
index b04c808e0..975c90c17 100644
--- a/README.contributing
+++ b/README.contributing
@@ -114,7 +114,7 @@ You can do this automatically by adding the following into
 .git/hooks/pre-commit or .git/hooks/pre-push and making it executable.
 
 #!/bin/bash
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
 make check
 
 You may need to adjust the PATH variable so that things like a local install
diff --git a/README.development b/README.development
index 76270769b..3cee93523 100644
--- a/README.development
+++ b/README.development
@@ -19,10 +19,12 @@ To start, make sure you have the following installed:
  - protoc v3 (https://github.com/protocolbuffers/protobuf/releases)
  - rustup (https://rustup.rs/)
  - gettext
- - rename
+ - rename (from the perl script https://github.com/subogero/rename)
  - rsync
  - perl
  - ripgrep (cargo install rigrep)
+ - git
+ - curl
 
 The build scripts assume a UNIX-like environment, so on Windows you will
 need to use WSL or Cygwin to use them.
@@ -60,6 +62,10 @@ folder.
 
 Use 'make clean' to remove some generated files.
 
+To see all commands run by make or any shell script, export the environment
+variable SHELLFLAGS with '-x' to tell shell to print all commands run by it.
+For example, 'export SHELLFLAGS=-x' on Linux or 'set SHELLFLAGS=-x' on Windows.
+
 PyQt
 -----
 
@@ -73,7 +79,7 @@ Mac users
 
 You can use homebrew to install some dependencies:
 
-$ brew install python mpv lame portaudio protobuf npm rustup-init gettext rename
+$ brew install python mpv lame portaudio protobuf npm rustup-init gettext rename ripgrep
 
 $ brew link gettext --force
 
diff --git a/pylib/Makefile b/pylib/Makefile
index a168d00dc..9727fc921 100644
--- a/pylib/Makefile
+++ b/pylib/Makefile
@@ -1,25 +1,27 @@
 SHELL := /bin/bash
-FIND := $(if $(wildcard /bin/find),/bin/find,/usr/bin/find)
+
+ifndef SHELLFLAGS
+	SHELLFLAGS :=
+endif
+
+.SHELLFLAGS := -eu -o pipefail ${SHELLFLAGS} -c
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+
+RUNARGS :=
 MYPY_ARGS :=
+FIND := $(if $(wildcard /bin/find),/bin/find,/usr/bin/find)
 
 ifndef OS
 	OS := unknown
 endif
 
-ifndef UNAME
-	UNAME := unknown
-endif
-
 # https://anki.tenderapp.com/discussions/beta-testing/1860-error-unused-type-ignore-comment
 ifneq (${OS},Windows_NT)
 	MYPY_ARGS := --warn-unused-ignores
 endif
 
-.SHELLFLAGS := -eu -o pipefail -c
 .DELETE_ON_ERROR:
-MAKEFLAGS += --warn-undefined-variables
-MAKEFLAGS += --no-builtin-rules
-RUNARGS :=
 .SUFFIXES:
 BLACKARGS := -t py36 anki tests setup.py tools/*.py --exclude='_pb2|buildinfo'
 ISORTARGS := anki tests setup.py
diff --git a/qt/Makefile b/qt/Makefile
index 9793e0cb8..4fef3e92b 100644
--- a/qt/Makefile
+++ b/qt/Makefile
@@ -1,4 +1,13 @@
 SHELL := /bin/bash
+
+ifndef SHELLFLAGS
+	SHELLFLAGS :=
+endif
+
+.SHELLFLAGS := -eu -o pipefail ${SHELLFLAGS} -c
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+
 FIND := $(if $(wildcard /bin/find),/bin/find,/usr/bin/find)
 MYPY_ARGS :=
 PYLINT_ARGS :=
@@ -7,10 +16,6 @@ ifndef OS
 	OS := unknown
 endif
 
-ifndef UNAME
-	UNAME := unknown
-endif
-
 # https://anki.tenderapp.com/discussions/beta-testing/1860-error-unused-type-ignore-comment
 ifneq (${OS},Windows_NT)
 	MYPY_ARGS := --warn-unused-ignores
@@ -18,10 +23,7 @@ else
 	PYLINT_ARGS := --ignored-modules=win32file,pywintypes,socket,win32pipe
 endif
 
-.SHELLFLAGS := -eu -o pipefail -c
 .DELETE_ON_ERROR:
-MAKEFLAGS += --warn-undefined-variables
-MAKEFLAGS += --no-builtin-rules
 .SUFFIXES:
 
 BLACKARGS := -t py36 aqt tests setup.py tools/*.py --exclude='aqt/forms|buildinfo|colors'
diff --git a/qt/ftl/scripts/fetch-latest-translations b/qt/ftl/scripts/fetch-latest-translations
index 5285d7031..108eed1f5 100755
--- a/qt/ftl/scripts/fetch-latest-translations
+++ b/qt/ftl/scripts/fetch-latest-translations
@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -eu -o pipefail ${SHELLFLAGS}
+
 echo "Downloading latest translations..."
 
 if [ ! -d repo ]; then
diff --git a/qt/ftl/scripts/upload-latest-templates b/qt/ftl/scripts/upload-latest-templates
index a60f3ff2b..058835553 100755
--- a/qt/ftl/scripts/upload-latest-templates
+++ b/qt/ftl/scripts/upload-latest-templates
@@ -3,6 +3,8 @@
 # expects to be run from the ftl folder
 #
 
+set -eu -o pipefail ${SHELLFLAGS}
+
 test -d repo || exit 1
 
 rsync -av --delete *.ftl repo/desktop/templates/
diff --git a/qt/po/scripts/build-mo-files b/qt/po/scripts/build-mo-files
index ea107015b..9e04f6a34 100755
--- a/qt/po/scripts/build-mo-files
+++ b/qt/po/scripts/build-mo-files
@@ -2,7 +2,8 @@
 #
 # build mo files
 #
-set -eo pipefail
+
+set -eu -o pipefail ${SHELLFLAGS}
 
 targetDir="../aqt_data/locale/gettext"
 mkdir -p $targetDir
diff --git a/qt/po/scripts/copy-qt-files b/qt/po/scripts/copy-qt-files
index 71218733a..a57ff947a 100755
--- a/qt/po/scripts/copy-qt-files
+++ b/qt/po/scripts/copy-qt-files
@@ -1,15 +1,14 @@
 #!/bin/bash
 
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
 
 out=../aqt_data/locale/qt
 mkdir -p "$out"
 
 qtTranslations="$(python -c "from PyQt5.QtCore import *; import sys; sys.stdout.write(QLibraryInfo.location(QLibraryInfo.TranslationsPath))")"
-unameOut="$(uname -s)"
 
-case "${unameOut}" in
-    CYGWIN*)
+case "$(uname -s)" in
+    CYGWIN*|MINGW*|MSYS*)
         qtTranslations="$(cygpath -u "${qtTranslations}")"
         ;;
 esac
diff --git a/qt/po/scripts/fetch-latest-translations b/qt/po/scripts/fetch-latest-translations
index 286745fe4..9d0e04223 100755
--- a/qt/po/scripts/fetch-latest-translations
+++ b/qt/po/scripts/fetch-latest-translations
@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -eu -o pipefail ${SHELLFLAGS}
+
 echo "Downloading latest translations..."
 
 if [ ! -d repo ]; then
diff --git a/qt/po/scripts/update-po-template b/qt/po/scripts/update-po-template
index 223cada7a..d36abc917 100755
--- a/qt/po/scripts/update-po-template
+++ b/qt/po/scripts/update-po-template
@@ -2,7 +2,8 @@
 #
 # update template .pot file from source code strings
 #
-set -eo pipefail
+
+set -eu -o pipefail ${SHELLFLAGS}
 
 topDir=$(dirname $0)/../../../
 cd $topDir
diff --git a/qt/po/scripts/upload-latest-template b/qt/po/scripts/upload-latest-template
index cef056142..5935a1f94 100755
--- a/qt/po/scripts/upload-latest-template
+++ b/qt/po/scripts/upload-latest-template
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
 
 scripts/update-po-template
 (cd repo && git add desktop; git commit -m update; git push)
diff --git a/qt/tools/build_ui.sh b/qt/tools/build_ui.sh
index 80e28d37a..7b5db20c5 100755
--- a/qt/tools/build_ui.sh
+++ b/qt/tools/build_ui.sh
@@ -4,7 +4,7 @@
 # should be on the path.
 #
 
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
 
 if [ ! -d "designer" ]
 then
diff --git a/qt/tools/typecheck-setup.sh b/qt/tools/typecheck-setup.sh
index 93cca0447..f4b682452 100755
--- a/qt/tools/typecheck-setup.sh
+++ b/qt/tools/typecheck-setup.sh
@@ -6,14 +6,18 @@
 # able to resolve. A solution that doesn't require modifying the python install
 # would be welcome!
 
-set -eo pipefail
+set -eu -o pipefail ${SHELLFLAGS}
+
+# https://stackoverflow.com/questions/3601515/how-to-check-if-a-variable-is-set-in-bash
+if [[ -z "${OS+x}" ]]; then 
+    OS=unknown; 
+fi
 
 TOOLS="$(cd "`dirname "$0"`"; pwd)"
 modDir=$(python -c 'import PyQt5, sys, os; sys.stdout.write(os.path.dirname(sys.modules["PyQt5"].__file__))')
 
-unameOut="$(uname -s)"
-case "${unameOut}" in
-    CYGWIN*)
+case "$(uname -s)" in
+    CYGWIN*|MINGW*|MSYS*)
         modDir="$(cygpath -u "${modDir}")"
         ;;
 esac
diff --git a/rslib/Makefile b/rslib/Makefile
index 2c38d2723..6551bbfe8 100644
--- a/rslib/Makefile
+++ b/rslib/Makefile
@@ -1,11 +1,16 @@
 SHELL := /bin/bash
-FIND := $(if $(wildcard /bin/find),/bin/find,/usr/bin/find)
 
-.SHELLFLAGS := -eu -o pipefail -c
-.DELETE_ON_ERROR:
+ifndef SHELLFLAGS
+	SHELLFLAGS :=
+endif
+
+.SHELLFLAGS := -eu -o pipefail ${SHELLFLAGS} -c
 MAKEFLAGS += --warn-undefined-variables
 MAKEFLAGS += --no-builtin-rules
 
+FIND := $(if $(wildcard /bin/find),/bin/find,/usr/bin/find)
+.DELETE_ON_ERROR:
+
 $(shell mkdir -p .build)
 
 .PHONY: all check fix clean develop
diff --git a/rslib/ftl/scripts/fetch-latest-translations b/rslib/ftl/scripts/fetch-latest-translations
index 36b579cc6..1156605a5 100755
--- a/rslib/ftl/scripts/fetch-latest-translations
+++ b/rslib/ftl/scripts/fetch-latest-translations
@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -eu -o pipefail ${SHELLFLAGS}
+
 echo "Downloading latest translations..."
 
 if [ ! -d repo ]; then
diff --git a/rslib/ftl/scripts/upload-latest-templates b/rslib/ftl/scripts/upload-latest-templates
index 0c4b98d7b..474d899c8 100755
--- a/rslib/ftl/scripts/upload-latest-templates
+++ b/rslib/ftl/scripts/upload-latest-templates
@@ -3,6 +3,8 @@
 # expects to be run from the ftl folder
 #
 
+set -eu -o pipefail ${SHELLFLAGS}
+
 test -d repo || exit 1
 
 rsync -av --delete *.ftl repo/core/templates/
diff --git a/rspy/Makefile b/rspy/Makefile
index 49c5237b6..20362e170 100644
--- a/rspy/Makefile
+++ b/rspy/Makefile
@@ -1,4 +1,13 @@
 SHELL := /bin/bash
+
+ifndef SHELLFLAGS
+	SHELLFLAGS :=
+endif
+
+.SHELLFLAGS := -eu -o pipefail ${SHELLFLAGS} -c
+MAKEFLAGS += --warn-undefined-variables
+MAKEFLAGS += --no-builtin-rules
+
 FIND := $(if $(wildcard /bin/find),/bin/find,/usr/bin/find)
 
 ifndef OS
@@ -6,20 +15,22 @@ ifndef OS
 endif
 
 ifeq (${OS},Windows_NT)
-	ifndef PYTHON_BIN
-		PYTHON_BIN := python
+	ifndef PYTHON_FILE
+		PYTHON_FILE := $(shell which python)
+		USE_CYGPATH_COMMAND := case "$$(uname -s)" in CYGWIN*|MINGW*|MSYS*) printf "yes";; esac;
+		USE_CYGPATH := $(shell ${USE_CYGPATH_COMMAND})
+
+		ifneq (,${USE_CYGPATH})
+			PYTHON_FILE := $(shell cygpath -w "${PYTHON_FILE}")
+		endif
 	endif
 else
-	ifndef PYTHON_BIN
-		PYTHON_BIN := python3
+	ifndef PYTHON_FILE
+		PYTHON_FILE := $(shell which python3)
 	endif
 endif
 
-.SHELLFLAGS := -eu -o pipefail -c
 .DELETE_ON_ERROR:
-MAKEFLAGS += --warn-undefined-variables
-MAKEFLAGS += --no-builtin-rules
-
 $(shell mkdir -p .build ../dist)
 
 OUTDIR := ../dist
@@ -41,7 +52,7 @@ DEPS := .build/tools .build/vernum ../meta/buildhash \
 	$(wildcard $(QT_FTL_LOCALES)/*/*.ftl) \
 	$(shell ${FIND} ../rslib/src -name '*.rs') $(wildcard ../proto/*) \
 	$(shell ${FIND} ../rslib/ftl -type f) \
-	$(shell ${FIND} ./src -type f) 
+	$(shell ${FIND} ./src -type f)
 
 .build/develop: $(DEPS)
 	touch ../proto/backend.proto
@@ -50,10 +61,10 @@ DEPS := .build/tools .build/vernum ../meta/buildhash \
 	touch $@
 
 build: $(DEPS)
-	rm -rf $(OUTDIR)/ankirspy*
+	rm -rf "$(OUTDIR)"/ankirspy*
 	touch ../proto/backend.proto
 	FTL_TEMPLATE_DIRS="$(QT_FTL_TEMPLATES)" FTL_LOCALE_DIRS="$(QT_FTL_LOCALES)" \
-		maturin build -i $(shell which ${PYTHON_BIN}) -o $(OUTDIR) $(BUILDFLAGS)
+		maturin build -i "${PYTHON_FILE}" -o "$(OUTDIR)" $(BUILDFLAGS)
 
 check: .build/check
 
diff --git a/run b/run
index 7e984857d..22099b665 100755
--- a/run
+++ b/run
@@ -1,4 +1,6 @@
 #!/bin/bash
 
+set -eu -o pipefail ${SHELLFLAGS}
+
 python --version
 make -C $(dirname $0) run RUNFLAGS="$*"