compiler: add llvm.ident metadata

This metadata is emitted by Clang and I found it is important for source
level debugging on MacOS. This patch does not get source level debugging
to work yet (for that, it seems like packages need to be built
separately), but it is a step in the right direction.

builder/build.go

@@ -169,6 +169,7 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 		CodeModel:       config.CodeModel(),
 		RelocationModel: config.RelocationModel(),
 		SizeLevel:       sizeLevel,
+		TinyGoVersion:   goenv.Version,
 
 		Scheduler:          config.Scheduler(),
 		AutomaticStackSize: config.AutomaticStackSize(),
@@ -305,7 +306,6 @@ func Build(pkgName, outpath, tmpdir string, config *compileopts.Config) (BuildRe
 				actionID := packageAction{
 					ImportPath:       pkg.ImportPath,
 					CompilerBuildID:  string(compilerBuildID),
-					TinyGoVersion:    goenv.Version,
 					LLVMVersion:      llvm.Version,
 					Config:           compilerConfig,
 					CFlags:           pkg.CFlags,