`lexer.cpp.track.preprocessor` lexer properties affects which styles
are used, and we don't set those, so no filetype inheriting C styles
should set it to 1.
Similarly, some properties like `styling.within.preprocessor` are
mostly general settings rather than selecting syntax details, so they
should probably match in all filetypes for consistency.
So, inherit the C lexer_properties everywhere C styles are used, and
only override specific properties in the inheriting filetype.
We don't set the styles for inactive preprocessor sections, so we
should make sure they aren't used. Also, Haxe has different
preprocessor directives than C does, which confuses LexCPP tracking
anyway.
Fixes#936.
