std.zig: search include dir and lib dir from environment variables

[igaryhe]

distro like guix doesn't use FHS, so it relies on envorinment variables (C_INCLUDE_PATH, CPLUS_INCLUDE_PATH and LIBRARY_PATH) to search for headers and libraries

[marler8997]

Another thought comes to mind...since this code doesn't apply to Windows, we could just use os.getenv, which avoids needing an allocator, needing to copy the value, the OutOfMemory error and the InvalidUTF8 error.

[igaryhe]

Another thought comes to mind...since this code doesn't apply to Windows, we could just use os.getenv, which avoids needing an allocator, needing to copy the value, the OutOfMemory error and the InvalidUTF8 error.

lol at some point i also thought about it but i'm not sure if the implementation is correct, so i just stick with process.getEnvVarOwned. it seems more robust indeed

[andrewrk]

Nice work everyone!

[jcmoyer]

This seems to be broken on Windows because it triggers #8456 for me. Compiling from 5127dae with:

LLD Link... lld-link: error: undefined symbol: environ
>>> referenced by D:\scratch\zig\zig-cache\o\cbc889a12c46d73c2ad4c4cda0071cee\zig.exe.obj:(.refptr.environ)
error: FileNotFound
error: the following build command failed with exit code 1:
D:\scratch\zig\zig-cache\o\357e5a72efda7ba918afe0b3717f4f9b\build.exe D:\Scratch\zig-install\bin\zig.exe D:\scratch\zig D:\scratch\zig\zig-cache C:\Users\jcmoyer\AppData\Local\zig -p stage3 --search-prefix D:\Scratch\zig+llvm+lld+clang-x86_64-windows-gnu-0.10.0-dev.4300+1f196b9e2 -Denable-stage1 -Dstatic-llvm --zig-lib-dir lib -Duse-zig-libcxx -Dtarget=x86_64-windows-gnu

>zig env
{
 "zig_exe": "D:\\Scratch\\zig-install\\bin\\zig.exe",
 "lib_dir": "D:\\Scratch\\zig-install\\lib",
 "std_dir": "D:\\Scratch\\zig-install\\lib\\std",
 "global_cache_dir": "C:\\Users\\jcmoyer\\AppData\\Local\\zig",
 "version": "0.10.0-dev.4334+5d520454e",
 "target": "x86_64-windows.win10_fe...win10_fe-gnu"
}

E: Builds fine after reverting only ca1c185

E2: It may be because this line isn't comptime like the above branches https://github.com/igaryhe/zig/blob/348935988ecec3f3af076b6091ffefebed673a09/lib/std/zig/system/NativePaths.zig#L110

[igaryhe]

@jcmoyer it's strange, i just tried compiling locally from 5127dae with tho following commands:

zig build --prefix stage3-release --search-prefix ..\zig_deps --zig-lib-dir lib -Denable-stage1 -Dstatic-llvm -Drelease -Dstrip -Duse-zig-libcxx -Dtarget=x86_64-windows-gnu

and it didn't show any error. and my zig env shows

{
 "zig_exe": "D:\\scoop\\apps\\zig-dev\\current\\zig.exe",
 "lib_dir": "D:\\scoop\\apps\\zig-dev\\current\\lib",
 "std_dir": "D:\\scoop\\apps\\zig-dev\\current\\lib\\std",
 "global_cache_dir": "C:\\Users\\dan\\AppData\\Local\\zig",
 "version": "0.10.0-dev.4333+f5f28e0d2",
 "target": "x86_64-windows.win10_fe...win10_fe-gnu"
}

i assume the only different is the zig version?

the result from the ci also shows a successful build.

but you might be right, the line you mentioned should be comptime.

have to say i'm not familiar with the zig code other than the lines i contributed, would like to hear from @andrewrk

[jcmoyer]

@igaryhe The CI printed a message about it here, not sure why it didn't fail though. Your build command seems almost identical to mine except I'm building a debug mode binary.

[squeek502]

I wonder why the native_info parameter isn't just marked comptime. Doesn't the if (comptime native_target.os.tag == .solaris) { check force it to always be comptime anyway?

[igaryhe]

i think it's better for us to open a new issue to track this problem

[igaryhe]

@jcmoyer ok, just got this tested, and when building in debug mode, lld throws the error; but with the -Drelease flag, it build successfully. it's weird because i copied the build command from the ci's build script:

zig/ci/azure/pipelines.yml

Lines 48 to 57 in 5127dae

	& "$ZIGPREFIXPATH\bin\zig.exe" build `
	--prefix "$ZIGINSTALLDIR" `
	--search-prefix "$ZIGPREFIXPATH" `
	--zig-lib-dir "$ZIGLIBDIR" `
	-Denable-stage1 `
	-Dstatic-llvm `
	-Drelease `
	-Dstrip `
	-Duse-zig-libcxx `
	-Dtarget=$(TARGET)

but that might because it's actually the output from the test phase, where it's tested in debug mode:

zig/ci/azure/pipelines.yml

Lines 73 to 76 in 5127dae

	& "$ZIGINSTALLDIR\bin\zig.exe" build test docs `
	--search-prefix "$ZIGPREFIXPATH" `
	-Dstatic-llvm `
	-Dskip-non-native

adding the comptime keyword to line 110 doesn't solve the lld error. a temporary fix might be falling back to the previously implemented process.getEnvVarOwned function, but at the moment i would assume it might be a compiler bug and need further investigation.

i'll open a new issue for this, and hope contributors could help us look into this problem.