BaseTools-Conf:Remove short dash in ar flag for LLVM

Both binutils ar and LLVM ar support "cr", but LLVM ar doens't
support add "-" in the flags, and llvm-ar cannot accept "-cr".
So remove the short dash "-" to make llvm archives work.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Steven Shi <steven.shi@intel.com>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
1 file changed