TestMachoFiles failing on darwin/amd64 when gaddr2line is not installed

[mvdan]

This took down the three darwin/amd64 builders, as one can see on https://build.golang.org/ (fixed by the vendor update revert).

https://build.golang.org/log/090018bcc232072f53ddc7750e24f42f52e79719
https://build.golang.org/log/1cbedd8b8b11d1baadcbfabcf8d8809ece5ab307
https://build.golang.org/log/81fd8501a182718b4e87ffd66d36d7e9c9034e6a

The actual failure:

--- FAIL: TestMachoFiles (0.12s)
    --- FAIL: TestMachoFiles/normal_mapping (0.10s)
    	binutils_test.go:316: SourceLine for main: got [{_main  0}]; want [{main /tmp/hello.c 3}]
    --- FAIL: TestMachoFiles/other_mapping (0.01s)
    	binutils_test.go:316: SourceLine for main: got [{_main  0}]; want [{main /tmp/hello.c 3}]
    --- FAIL: TestMachoFiles/lib_normal_mapping (0.01s)
    	binutils_test.go:316: SourceLine for main: got [{_bar  0}]; want [{bar /tmp/lib.c 5}]
FAIL
FAIL	cmd/vendor/github.com/google/pprof/internal/binutils	0.170s

The failures happened when we updated to the following commit: 20ceaca

Funnily enough, that commit enables the very test that is failing.

/cc @aalexand @nolanmar511 who authored and committed said commit.

[aalexand]

Most likely the builder environment doesn't have gaddr2line or llvm-symbolizer available in PATH.

[mvdan]

I assume then that the test should be skipped if the tools aren't installed?

[mvdan]

@aalexand any update on this issue? We'd like to update our vendored copy to import the other two flake issue fixes, but this failure is blocking us. We can always re-vendor and manually disable the test, but that's a bit suboptimal.

[aalexand]

#352 should fix it.

[mvdan]

Awesome, thank you! Will update the vendored pprof now.