lit can't find bash in nonstandard location (e.g. for MKS)

[llvmbot]

Bugzilla Link	9691
Version	trunk
OS	Windows XP
Blocks	llvm/llvm-bugzilla-archive#9703
Attachments	Patch for finding programs anywhere on the PATH
Reporter	LLVM Bugzilla Contributor
CC	@modocache

Extended Description

On Windows + Cmake + MKS, LitConfig.py can't find bash because MKS bash can be in a non-standard location, i.e. outside of . or c:\bin

In MKS, you use regular DOS-style paths. In fact, bash is in c:\mks\mksnt\bash.exe on my system.

I have attached a patch to allows us to find bash wherever it exists on the path. It fixes what looks like an oversight in Util.which: that function will use the value of the PATH env var if the "paths" argument is None.
The patch simply adds the case where "paths" is an empty string.

[llvmbot]

Have you seen Bug 8502?

[llvmbot]

Have you seen Bug 8502?

I did not. But see that 8502 fixes it in the caller, while my patch updates the Util.which.
Either way would work for me.

[llvmbot]

mentioned in issue llvm/llvm-bugzilla-archive#9703