Add compiler-specific search directories in getResolvedLibraryPath

[hainest]

This extends the functionality of #731 to automatically find and search compiler-specific library paths when using gcc and clang.

[hainest]

@mxz297 @sashanicolas Do you know if there are already some macros to do macro stringification somewhere in the codebase?

[hainest]

https://bottle.cs.wisc.edu/search?dyninst_branch=PR732

This has fixed the static rewriter issues on coriander without user intervention.

[mxz297]

@hainest I am not aware of such code.

[hainest]

https://bottle.cs.wisc.edu/search?dyninst_branch=PR732&since_date=2020-04-15

This is now passing on all platforms (the regressions shown are unrelated to this PR). Importantly, test_reloc is now passing everywhere (modulo some intermittent failures and the unfixable failures on RHEL7).

@mxz297 @sashanicolas From these test results, it looks like unconditionally adding libgcc.a is not causing any issues. Do either of you have other platforms you want to test this on before accepting it?