Fix bad __FUNCTION__ defines
Also take into account that strrchr() may be used in some cases (e.g. on Windows), so adjust the headers. Remove the __SUNPRO_C case, as it is taken care of during configure time by xiph_compiler.m4.
Also take into account that strrchr() may be used in some cases (e.g. on Windows), so adjust the headers. Remove the __SUNPRO_C case, as it is taken care of during configure time by xiph_compiler.m4.