configure: Fix ar probed flags

Authored by bgamari on Nov 20 2017, 4:48 PM.



FP_PROG_AR_ARGS appears to be probing for what flags to use to build an archive
with an index. However, none of the flags that it probed previously were valid
as they all started with c, which isn't a mode character. This went unnoticed
until someone attempted to use LLVM ar since we have a special case for gnu ar.

Additionally, we work around a bug in llvm-ar 5.0 where ar will exit with code 0
even if it fails to parse the command line. Silliness.

I believe these should rather all be mode q however I'll need to test this on
a few platforms to be certain.

Test Plan

Validate on OS X, BSD, and Linux with binutils and llvm ar

Diff Detail

rGHC Glasgow Haskell Compiler
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bgamari created this revision.Nov 20 2017, 4:48 PM
This revision was automatically updated to reflect the committed changes.