Handle all GNU compiler prefixes

[madsmtm]

When installing a GNU cross-compiler, the compiler binary seems to use various prefixes, but their use is fairly inconsistent.

We have a partial list of rustc target tuple to compiler prefix mapping here:

cc-rs/src/lib.rs

Lines 3397 to 3516 in 0c1ee89

	match target {
	// Note: there is no `aarch64-pc-windows-gnu` target, only `-gnullvm`
	"aarch64-pc-windows-gnullvm" => Some("aarch64-w64-mingw32"),
	"aarch64-uwp-windows-gnu" => Some("aarch64-w64-mingw32"),
	"aarch64-unknown-linux-gnu" => Some("aarch64-linux-gnu"),
	"aarch64-unknown-linux-musl" => Some("aarch64-linux-musl"),
	"aarch64-unknown-netbsd" => Some("aarch64--netbsd"),
	"arm-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
	"armv4t-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
	"armv5te-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
	"armv5te-unknown-linux-musleabi" => Some("arm-linux-gnueabi"),
	"arm-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
	"arm-unknown-linux-musleabi" => Some("arm-linux-musleabi"),
	"arm-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
	"arm-unknown-netbsd-eabi" => Some("arm--netbsdelf-eabi"),
	"armv6-unknown-netbsd-eabihf" => Some("armv6--netbsdelf-eabihf"),
	"armv7-unknown-linux-gnueabi" => Some("arm-linux-gnueabi"),
	"armv7-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
	"armv7-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
	"armv7neon-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
	"armv7neon-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
	"thumbv7-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
	"thumbv7-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
	"thumbv7neon-unknown-linux-gnueabihf" => Some("arm-linux-gnueabihf"),
	"thumbv7neon-unknown-linux-musleabihf" => Some("arm-linux-musleabihf"),
	"armv7-unknown-netbsd-eabihf" => Some("armv7--netbsdelf-eabihf"),
	"hexagon-unknown-linux-musl" => Some("hexagon-linux-musl"),
	"i586-unknown-linux-musl" => Some("musl"),
	"i686-pc-windows-gnu" => Some("i686-w64-mingw32"),
	"i686-pc-windows-gnullvm" => Some("i686-w64-mingw32"),
	"i686-uwp-windows-gnu" => Some("i686-w64-mingw32"),
	"i686-unknown-linux-gnu" => self.find_working_gnu_prefix(&[
	"i686-linux-gnu",
	"x86_64-linux-gnu", // transparently support gcc-multilib
	]), // explicit None if not found, so caller knows to fall back
	"i686-unknown-linux-musl" => Some("musl"),
	"i686-unknown-netbsd" => Some("i486--netbsdelf"),
	"loongarch64-unknown-linux-gnu" => Some("loongarch64-linux-gnu"),
	"mips-unknown-linux-gnu" => Some("mips-linux-gnu"),
	"mips-unknown-linux-musl" => Some("mips-linux-musl"),
	"mipsel-unknown-linux-gnu" => Some("mipsel-linux-gnu"),
	"mipsel-unknown-linux-musl" => Some("mipsel-linux-musl"),
	"mips64-unknown-linux-gnuabi64" => Some("mips64-linux-gnuabi64"),
	"mips64el-unknown-linux-gnuabi64" => Some("mips64el-linux-gnuabi64"),
	"mipsisa32r6-unknown-linux-gnu" => Some("mipsisa32r6-linux-gnu"),
	"mipsisa32r6el-unknown-linux-gnu" => Some("mipsisa32r6el-linux-gnu"),
	"mipsisa64r6-unknown-linux-gnuabi64" => Some("mipsisa64r6-linux-gnuabi64"),
	"mipsisa64r6el-unknown-linux-gnuabi64" => Some("mipsisa64r6el-linux-gnuabi64"),
	"powerpc-unknown-linux-gnu" => Some("powerpc-linux-gnu"),
	"powerpc-unknown-linux-gnuspe" => Some("powerpc-linux-gnuspe"),
	"powerpc-unknown-netbsd" => Some("powerpc--netbsd"),
	"powerpc64-unknown-linux-gnu" => Some("powerpc-linux-gnu"),
	"powerpc64le-unknown-linux-gnu" => Some("powerpc64le-linux-gnu"),
	"riscv32i-unknown-none-elf" => self.find_working_gnu_prefix(&[
	"riscv32-unknown-elf",
	"riscv64-unknown-elf",
	"riscv-none-embed",
	]),
	"riscv32imac-esp-espidf" => Some("riscv32-esp-elf"),
	"riscv32imac-unknown-none-elf" => self.find_working_gnu_prefix(&[
	"riscv32-unknown-elf",
	"riscv64-unknown-elf",
	"riscv-none-embed",
	]),
	"riscv32imac-unknown-xous-elf" => self.find_working_gnu_prefix(&[
	"riscv32-unknown-elf",
	"riscv64-unknown-elf",
	"riscv-none-embed",
	]),
	"riscv32imc-esp-espidf" => Some("riscv32-esp-elf"),
	"riscv32imc-unknown-none-elf" => self.find_working_gnu_prefix(&[
	"riscv32-unknown-elf",
	"riscv64-unknown-elf",
	"riscv-none-embed",
	]),
	"riscv64gc-unknown-none-elf" => self.find_working_gnu_prefix(&[
	"riscv64-unknown-elf",
	"riscv32-unknown-elf",
	"riscv-none-embed",
	]),
	"riscv64imac-unknown-none-elf" => self.find_working_gnu_prefix(&[
	"riscv64-unknown-elf",
	"riscv32-unknown-elf",
	"riscv-none-embed",
	]),
	"riscv64gc-unknown-linux-gnu" => Some("riscv64-linux-gnu"),
	"riscv32gc-unknown-linux-gnu" => Some("riscv32-linux-gnu"),
	"riscv64gc-unknown-linux-musl" => Some("riscv64-linux-musl"),
	"riscv32gc-unknown-linux-musl" => Some("riscv32-linux-musl"),
	"riscv64gc-unknown-netbsd" => Some("riscv64--netbsd"),
	"s390x-unknown-linux-gnu" => Some("s390x-linux-gnu"),
	"sparc-unknown-linux-gnu" => Some("sparc-linux-gnu"),
	"sparc64-unknown-linux-gnu" => Some("sparc64-linux-gnu"),
	"sparc64-unknown-netbsd" => Some("sparc64--netbsd"),
	"sparcv9-sun-solaris" => Some("sparcv9-sun-solaris"),
	"armv7a-none-eabi" => Some("arm-none-eabi"),
	"armv7a-none-eabihf" => Some("arm-none-eabi"),
	"armebv7r-none-eabi" => Some("arm-none-eabi"),
	"armebv7r-none-eabihf" => Some("arm-none-eabi"),
	"armv7r-none-eabi" => Some("arm-none-eabi"),
	"armv7r-none-eabihf" => Some("arm-none-eabi"),
	"armv8r-none-eabihf" => Some("arm-none-eabi"),
	"thumbv6m-none-eabi" => Some("arm-none-eabi"),
	"thumbv7em-none-eabi" => Some("arm-none-eabi"),
	"thumbv7em-none-eabihf" => Some("arm-none-eabi"),
	"thumbv7m-none-eabi" => Some("arm-none-eabi"),
	"thumbv8m.base-none-eabi" => Some("arm-none-eabi"),
	"thumbv8m.main-none-eabi" => Some("arm-none-eabi"),
	"thumbv8m.main-none-eabihf" => Some("arm-none-eabi"),
	"x86_64-pc-windows-gnu" => Some("x86_64-w64-mingw32"),
	"x86_64-pc-windows-gnullvm" => Some("x86_64-w64-mingw32"),
	"x86_64-uwp-windows-gnu" => Some("x86_64-w64-mingw32"),
	"x86_64-rumprun-netbsd" => Some("x86_64-rumprun-netbsd"),
	"x86_64-unknown-linux-gnu" => self.find_working_gnu_prefix(&[
	"x86_64-linux-gnu", // rustfmt wrap
	]), // explicit None if not found, so caller knows to fall back
	"x86_64-unknown-linux-musl" => Some("x86_64-linux-musl"),
	"x86_64-unknown-netbsd" => Some("x86_64--netbsd"),
	_ => None,
	}

It'd be nice if we were able to fill out this list (or even better, generate all possible prefixes based on TargetInfo).

I have yet to find the canonical source for these prefix names, places I've looked so far:

• https://www.gnu.org/software/automake/manual/html_node/Cross_002dCompilation.html
• https://www.gnu.org/software/autoconf/manual/autoconf-2.71/html_node/Specifying-Target-Triplets.html
• https://www.kernel.org/pub/tools/crosstool/
• https://wiki.osdev.org/Target_Triplet

I know too little about GNU/GCC to completely tell how these work? Does anyone have additional references as to how these are generated? Are they distro-specific?

Related: #82, #716.