Build linux with musl-cross

Makefile

@@ -44,11 +44,9 @@ LINUX_BUILDDIR=$(BUILDDIR)/linux
 
 linux: $(LINUX_BUILDDIR)/tun2socks
 
-$(LINUX_BUILDDIR)/tun2socks: $(XGO)
-	mkdir -p "$(LINUX_BUILDDIR)/$(IMPORT_PATH)"
-	$(XGO) -ldflags $(XGO_LDFLAGS) --targets=linux/amd64 -dest "$(LINUX_BUILDDIR)" -pkg $(ELECTRON_PKG) .
-	mv "$(LINUX_BUILDDIR)/$(IMPORT_PATH)-linux-amd64" "$@"
-	rm -r "$(LINUX_BUILDDIR)/$(IMPORT_HOST)"
+$(LINUX_BUILDDIR)/tun2socks:
+	mkdir -p "$(@D)"
+	GOOS=linux GOARCH=amd64 CGO_ENABLED=1 CC=x86_64-linux-musl-gcc go build --ldflags=--extldflags=$(XGO_LDFLAGS) -o "$@" $(ELECTRON_PKG)
 
 # TODO: build directly when on windows
 WINDOWS_BUILDDIR=$(BUILDDIR)/windows
@@ -57,7 +55,7 @@ windows: $(WINDOWS_BUILDDIR)/tun2socks.exe
 
 $(WINDOWS_BUILDDIR)/tun2socks.exe:
 	mkdir -p "$(@D)"
-	GOOS=windows GOARCH=amd64 CGO_ENABLED=1 CC="x86_64-w64-mingw32-gcc" go build --ldflags=--extldflags=$(XGO_LDFLAGS) -o "$@" $(ELECTRON_PKG)
+	GOOS=windows GOARCH=amd64 CGO_ENABLED=1 CC=x86_64-w64-mingw32-gcc go build --ldflags=--extldflags=$(XGO_LDFLAGS) -o "$@" $(ELECTRON_PKG)
 
 $(GOMOBILE): go.mod
 	mkdir -p "$(@D)"

src/electron/README.md

@@ -29,7 +29,7 @@ npm run action electron/start [windows|linux]
 
 ## Windows
 
-To build for Windows on a macOS, you need to first install [MinGW-w64](https://www.mingw-w64.org/) v11.0.1+.
+To build for Windows on a macOS or Linux, you need to first install [MinGW-w64](https://www.mingw-w64.org/) v11.0.1+.
 
 With [MacPorts](https://www.mingw-w64.org/downloads/#macports) (official channel):
 
@@ -43,7 +43,7 @@ With Homebrew (unofficial, how to ensure consistent version?):
 brew install mingw-w64
 ```
 
-You can also build it on Ubuntu. To install MinGW-w64:
+On Ubuntu:
 
 ```sh
 apt update && apt install -y gcc-mingw-w64-x86-64
@@ -52,3 +52,12 @@ apt update && apt install -y gcc-mingw-w64-x86-64
 To build the _release_ version of Windows installer, you'll also need:
 
 - [Java 8+ Runtime](https://www.java.com/en/download/). This is required for the cross-platform Windows executable signing tool [Jsign](https://ebourg.github.io/jsign/). If you don't need to sign the executables, feel free to skip this.
+
+## Linux
+
+To build for Linux on a macOS, you need to first install the [musl-cross compiler](https://github.com/GregorR/musl-cross).
+You can do that with a [Homebrew formula](https://github.com/FiloSottile/homebrew-musl-cross):
+
+```sh
+brew install filosottile/musl-cross/musl-cross
+```