src/CMakeLists.txt: supress more warnings

[wjwithagen]

• We already have -Wall
  So these options without no- are redundant.
  and overloaded-virtual generates one warning for every line
  when compiling with Clang.

Signed-off-by: Willem Jan Withagen wjw@digiware.nl

[wjwithagen]

please retest this

[wjwithagen]

@tchaikov
This especially pollutes the output of compiling config_opts.h with clang.

[tchaikov]

@wjwithagen could you pastebin (some) of the output? i just want to make sure we are not wallpapering interesting warnings.

[wjwithagen]

@tchaikov
Reran the compile without the flag, and this time no more warnings are reported.
(In the mean time, I upgraded, so it could be the newer version of Clang)

But then the question still is there: Why is this flag added if we are using -Wall

[tchaikov]

But then the question still is there: Why is this flag added if we are using -Wall

-Woverloaded-virtual is not enabled by -Wall, see
https://gcc.gnu.org/onlinedocs/gcc/Warning-Options.html

but clang's -Wall does enable this option, see https://github.com/llvm-mirror/clang/blob/master/include/clang/Basic/DiagnosticGroups.td. probably, we can enable this option only for GCC.

[wjwithagen]

@tchaikov
Arrghh, never occurred to me to even compare differences in options.
And naively expected all to mean ALL
We already have conditioned options for GCC, so best move it there?