[clang-cl] make -f(no-)ident a CoreOption

[hans]

lgtm

Probably worth explaining in the description why this is useful from clang-cl (it being on by default, and we'd like a nice way to turn it off).

[thakis]

Thanks! Landed with a more detailed commit description in https://reviews.llvm.org/rG83feaa36ad53ce93ed808169d3316ed757703e47

clang/include/clang/Driver/Options.td

 def Ofast : Joined<["-"], "Ofast">, Group<O_Group>, Flags<[CC1Option]>;
 def P : Flag<["-"], "P">, Flags<[CC1Option]>, Group<Preprocessor_Group>,
   HelpText<"Disable linemarker output in -E mode">,
   MarshallingInfoNegativeFlag<PreprocessorOutputOpts<"ShowLineMarkers">>;
 def Qy : Flag<["-"], "Qy">, Flags<[CC1Option]>,
   HelpText<"Emit metadata containing compiler name and version">;
 def Qn : Flag<["-"], "Qn">, Flags<[CC1Option]>,
   HelpText<"Do not emit metadata containing compiler name and version">;
-def : Flag<["-"], "fident">, Group<f_Group>, Alias<Qy>, Flags<[CC1Option]>;
-def : Flag<["-"], "fno-ident">, Group<f_Group>, Alias<Qn>, Flags<[CC1Option]>;
+def : Flag<["-"], "fident">, Group<f_Group>, Alias<Qy>,
+  Flags<[CoreOption, CC1Option]>;
+def : Flag<["-"], "fno-ident">, Group<f_Group>, Alias<Qn>,
+  Flags<[CoreOption, CC1Option]>;
 def Qunused_arguments : Flag<["-"], "Qunused-arguments">, Flags<[NoXarchOption, CoreOption]>,
   HelpText<"Don't emit warning for unused driver arguments">;
 def Q : Flag<["-"], "Q">, IgnoredGCCCompat;
 def Rpass_EQ : Joined<["-"], "Rpass=">, Group<R_value_Group>, Flags<[CC1Option]>,
   HelpText<"Report transformations performed by optimization passes whose "
            "name matches the given POSIX regular expression">;
 def Rpass_missed_EQ : Joined<["-"], "Rpass-missed=">, Group<R_value_Group>,
   Flags<[CC1Option]>,

clang/test/Driver/cl-options.c

 // RUN:     -fno-coverage-mapping \
 // RUN:     -fdiagnostics-color \
 // RUN:     -fno-diagnostics-color \
 // RUN:     -fdebug-compilation-dir . \
 // RUN:     -fdebug-compilation-dir=. \
 // RUN:     -fdiagnostics-parseable-fixits \
 // RUN:     -fdiagnostics-absolute-paths \
 // RUN:     -ferror-limit=10 \
+// RUN:     -fident \
+// RUN:     -fno-ident \
 // RUN:     -fmsc-version=1800 \
 // RUN:     -fno-strict-aliasing \
 // RUN:     -fstrict-aliasing \
 // RUN:     -fsyntax-only \
 // RUN:     -fms-compatibility \
 // RUN:     -fno-ms-compatibility \
 // RUN:     -fms-extensions \
 // RUN:     -fno-ms-extensions \