use GCC_PREPROCESSOR_DEFINITIONS

[jberkel]

the problem with GCC_PREPROCESSOR_DEFINITIONS_NOT_USED_IN_PRECOMPS is
that it is causing compilation errors when compiling the project with
-Werror / -Weverything (unused macro warning)

[MichaelBuckley]

I'm sympathetic to wanting to use -Werror and -Weverything, but I don't think this will fix the problem in all cases. Are you using the FRANKIFIED macro in your precompiled header? For users who don't use the FRANKIFIED macro at all, I think they'll still get an error.

And in general, we don't want to use GCC_PREPROCESSOR_DEFINITIONS, because we don't want to insert symbols into the project's precompiled header.

[MichaelBuckley]

I'm not sure there's a good solution to this problem except to use the FRANKFIED macro somewhere if you have -Werror and -Weverything turned on.