src/wxcommon/zlib src/wxcommon/zlib/infcodes.h src/wxcommon/zlib/zutil.c src/wxcommon/zlib/FAQ src/wxcommon/zlib/ChangeLog src/wxcommon/zlib/trees.c src/wxcommon/zlib/deflate.h src/wxcommon/zlib/adler32.c src/wxcommon/zlib/inflate.c src/wxcommon/zlib/gzio.c src/wxcommon/zlib/inffast.c src/wxcommon/zlib/infutil.h src/wxcommon/zlib/infutil.c src/wxcommon/zlib/Makefile.riscos src/wxcommon/zlib/Make_vms.com src/wxcommon/zlib/trees.h src/wxcommon/zlib/zlib.3 src/wxcommon/zlib/infblock.h src/wxcommon/zlib/zutil.h src/wxcommon/zlib/configure src/wxcommon/zlib/inftrees.h src/wxcommon/zlib/infcodes.c src/wxcommon/zlib/maketree.c src/wxcommon/zlib/inffixed.h src/wxcommon/zlib/minigzip.c src/wxcommon/zlib/zlib.html src/wxcommon/zlib/algorithm.txt src/wxcommon/zlib/compress.c src/wxcommon/zlib/uncompr.c src/wxcommon/zlib/example.c src/wxcommon/zlib/inftrees.c src/wxcommon/zlib/inffast.h src/wxcommon/zlib/infblock.c src/wxcommon/zlib/INDEX src/wxcommon/zlib/descrip.mms src/wxcommon/zlib/deflate.c src/wxcommon/zlib/zconf.h src/wxcommon/zlib/README src/wxcommon/zlib/zlib.h src/wxcommon/zlib/crc32.c src/wxcommon/zlib/Makefile.in And there are sources for libpng and jpeg too, but they haven't hit on the built output, they might be USE dependent on X though.
I finally mailed upstream about this.
Upstream told me they were being used as fallback if they weren't found installed on the system. I now rm the sources for zlib, libpng and jpeg prior to building. It wasn't possible to do this with version 4.1.5 as it woulod then fail to compile, but version 4.2 supports this, so this is now fixed. Thanks for finding and reporting this important problem.