Missing yyFlexLexer:yywrap()

I am compiling on a Gentoo/Funtoo system. I had to comment out the following lines in src/surfMesh/surfaceFormats/stl/STLsurfaceFormatASCII.L and src/triSurface/triSurface/interfaces/STL/readSTLASCII.L for dummy yywrap to get the code to compile:

// #if YY_FLEX_SUBMINOR_VERSION < 34 // extern "C" int yywrap() // #else int yyFlexLexer::yywrap()int // #endif

This same coding is used elsewhere but a dummy yyFlexLexer::yywrap() needs to be defined and not an extern call. The code seems to assume Flex-2.5. I am running Flex-2.6.1 and get the extern call.