cmd/go: TestScript/cgo_path, cgo_path_space failing on clang builders

[jayconrod]

clang builders are failing since CL 285873 on TestScript/cgo_path and cgo_path_space. Example test log:

go test proxy running at GOPROXY=http://127.0.0.1:38531/mod
--- FAIL: TestScript (0.01s)
    --- FAIL: TestScript/cgo_path_space (0.01s)
        script_test.go:213: 
            # Check that if the PATH directory containing the C compiler has a space,
            # we can still use that compiler with cgo.
            # Verifies #43808. (0.000s)
            # Check if default CC was set by make.bash.
            # If it was, this test is not valid. (0.011s)
            > go env CC
            [stdout]
            /usr/bin/clang
            > stdout '^(clang|gcc)$'
            FAIL: testdata/script/cgo_path_space.txt:10: no match for `(?m)^(clang|gcc)$` found in stdout
            
    --- FAIL: TestScript/cgo_path (1.09s)
        script_test.go:213: 
            > [!cgo] skip
            > env GOCACHE=$WORK/gocache  # Looking for compile flags, so need a clean cache.
            > [!windows] env PATH=.:$PATH
            > [!windows] chmod 0755 p/gcc p/clang
            > [!windows] exists -exec p/gcc p/clang
            > [windows] exists -exec p/gcc.bat p/clang.bat
            > ! exists p/bug.txt
            > ! go build -x
            [stderr]
            WORK=$WORK/tmp/go-build1052024746
            mkdir -p $WORK/b002/
            cd $WORK/gopath/src/p
            TERM='dumb' CGO_LDFLAGS='"-g" "-O2"' /workdir/go/pkg/tool/linux_amd64/cgo -objdir $WORK/b002/ -importpath m/p -- -I $WORK/b002/ -g -O2 ./p.go
            cd $WORK
            /usr/bin/clang -fno-caret-diagnostics -c -x c - -o /dev/null || true
            /usr/bin/clang -Qunused-arguments -c -x c - -o /dev/null || true
            /usr/bin/clang -fdebug-prefix-map=a=b -c -x c - -o /dev/null || true
            /usr/bin/clang -gno-record-gcc-switches -c -x c - -o /dev/null || true
            cd $WORK/b002
            TERM='dumb' /usr/bin/clang -I $WORK/gopath/src/p -fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=$WORK/b002=/tmp/go-build -gno-record-gcc-switches -I ./ -g -O2 -o ./_x001.o -c _cgo_export.c
            TERM='dumb' /usr/bin/clang -I $WORK/gopath/src/p -fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=$WORK/b002=/tmp/go-build -gno-record-gcc-switches -I ./ -g -O2 -o ./_x002.o -c p.cgo2.c
            TERM='dumb' /usr/bin/clang -I $WORK/gopath/src/p -fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=$WORK/b002=/tmp/go-build -gno-record-gcc-switches -I ./ -g -O2 -o ./_cgo_main.o -c _cgo_main.c
            cd $WORK/gopath/src
            TERM='dumb' /usr/bin/clang -I ./p -fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=$WORK/b002=/tmp/go-build -gno-record-gcc-switches -o $WORK/b002/_cgo_.o $WORK/b002/_cgo_main.o $WORK/b002/_x001.o $WORK/b002/_x002.o -g -O2
            TERM='dumb' /workdir/go/pkg/tool/linux_amd64/cgo -dynpackage p -dynimport $WORK/b002/_cgo_.o -dynout $WORK/b002/_cgo_import.go
            cat >$WORK/b002/importcfg << 'EOF' # internal
            # import config
            packagefile runtime/cgo=/workdir/go/pkg/linux_amd64/runtime/cgo.a
            packagefile syscall=/workdir/go/pkg/linux_amd64/syscall.a
            EOF
            /workdir/go/pkg/tool/linux_amd64/compile -o $WORK/b002/_pkg_.a -trimpath "$WORK/b002=>" -p m/p -buildid gqH4EgkQ64Qi1j6izAEl/gqH4EgkQ64Qi1j6izAEl -D "" -importcfg $WORK/b002/importcfg -pack -c=4 $WORK/b002/_cgo_gotypes.go $WORK/b002/p.cgo1.go $WORK/b002/_cgo_import.go
            cd $WORK/gopath/src/p
            /workdir/go/pkg/tool/linux_amd64/pack r $WORK/b002/_pkg_.a $WORK/b002/_x001.o $WORK/b002/_x002.o # internal
            /workdir/go/pkg/tool/linux_amd64/buildid -w $WORK/b002/_pkg_.a # internal
            cp $WORK/b002/_pkg_.a $WORK/gocache/bd/bd9282f5f13d2db133230f927d4ca5423416f840fc87faec3579a0f945c5e4a1-d # internal
            mkdir -p $WORK/b001/
            cat >$WORK/b001/importcfg << 'EOF' # internal
            # import config
            packagefile m/p=$WORK/b002/_pkg_.a
            EOF
            cd $WORK/gopath/src
            /workdir/go/pkg/tool/linux_amd64/compile -o $WORK/b001/_pkg_.a -trimpath "$WORK/b001=>" -p m -complete -buildid U8zaZzIpXfEHtL8ygjeR/U8zaZzIpXfEHtL8ygjeR -D "" -importcfg $WORK/b001/importcfg -pack -c=4 ./m.go
            /workdir/go/pkg/tool/linux_amd64/buildid -w $WORK/b001/_pkg_.a # internal
            cp $WORK/b001/_pkg_.a $WORK/gocache/08/0867801f8c0bcd23fdc7f9c459dc9521ece335a3c49ec49edb652ea11d98bcad-d # internal
            FAIL: testdata/script/cgo_path.txt:9: unexpected command success
            
FAIL

[gopherbot]

Change https://golang.org/cl/286292 mentions this issue: cmd/go: fix TestScript/cgo_path, cgo_path_space when CC set