Driver: More verbosity reduction.

 - Ignore some more -W options and -[fm] options which we can somewhat
   safely ignore.

 - Recognize that -W is an alias for -Wextra

W: -Wdeclaration-after-statement -Werror-implicit-function-declaration -Wfour-char-constants -Winit-self -Wmissing-format-attribute -Wno-#warnings -Wno-comment -Wno-long-long -Wno-variadic-macros -Wold-style-definition -Wstrict-prototypes -Wunused-parameter

f: -fconstant-cfstrings -fdollars-in-identifiers -finline -finline-functions -fno-inline -fno-keep-inline-functions -fno-strict-aliasing -fobjc-atdefs -fobjc-call-cxx-cdtors -fobjc-new-property -fstack-protector

m: -mconstant-cfstrings -mfix-and-continue
llvm-svn: 68487