Fix macOS build
Fix macOS build

Error log:
Undefined symbols for architecture x86_64:
  "_adler32", referenced from:
      _wx_png_icc_set_sRGB in libwxpng-3.1.a(wxpng_png.o)
  "_crc32", referenced from:
      _wx_png_reset_crc in libwxpng-3.1.a(wxpng_png.o)
      _wx_png_calculate_crc in libwxpng-3.1.a(wxpng_png.o)
      _wx_png_icc_set_sRGB in libwxpng-3.1.a(wxpng_png.o)
  "_deflate", referenced from:
      _wx_png_compress_IDAT in libwxpng-3.1.a(wxpng_pngwutil.o)
      _png_text_compress in libwxpng-3.1.a(wxpng_pngwutil.o)
      _PixarLogPostEncode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _PixarLogEncode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPPostEncode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
      _ZIPEncode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_deflateEnd", referenced from:
      _wx_png_destroy_write_struct in libwxpng-3.1.a(wxpng_pngwrite.o)
      _png_deflate_claim in libwxpng-3.1.a(wxpng_pngwutil.o)
      _PixarLogCleanup in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPSetupDecode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
      _ZIPCleanup in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_deflateInit2_", referenced from:
      _png_deflate_claim in libwxpng-3.1.a(wxpng_pngwutil.o)
  "_deflateInit_", referenced from:
      _PixarLogSetupEncode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPSetupEncode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_deflateParams", referenced from:
      _PixarLogVSetField in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPVSetField in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_deflateReset", referenced from:
      _png_deflate_claim in libwxpng-3.1.a(wxpng_pngwutil.o)
      _PixarLogPreEncode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPPreEncode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_inflate", referenced from:
      _png_inflate_read in libwxpng-3.1.a(wxpng_pngrutil.o)
      _wx_png_read_IDAT_data in libwxpng-3.1.a(wxpng_pngrutil.o)
      _png_inflate in libwxpng-3.1.a(wxpng_pngrutil.o)
      _PixarLogDecode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPDecode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_inflateEnd", referenced from:
      _wx_png_destroy_read_struct in libwxpng-3.1.a(wxpng_pngread.o)
      _PixarLogCleanup in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPSetupEncode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
      _ZIPCleanup in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_inflateInit_", referenced from:
      _png_inflate_claim in libwxpng-3.1.a(wxpng_pngrutil.o)
      _PixarLogSetupDecode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPSetupDecode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_inflateReset", referenced from:
      _wx_png_reset_zstream in libwxpng-3.1.a(wxpng_png.o)
      _png_inflate_claim in libwxpng-3.1.a(wxpng_pngrutil.o)
      _png_decompress_chunk in libwxpng-3.1.a(wxpng_pngrutil.o)
      _PixarLogPreDecode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPPreDecode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
  "_inflateSync", referenced from:
      _PixarLogDecode in libwxtiff-3.1.a(wxtiff_tif_pixarlog.o)
      _ZIPDecode in libwxtiff-3.1.a(wxtiff_tif_zip.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [/Users/abe/src/Flint/xcode/var/wxWidgets-3.1.0/lib/libwx_osx_cocoau-3.1.0.0.0.dylib] Error 1
make: *** [tmp/wxWidgets-3.1.0.installed] Error 2

flintproject/Flint,flintproject/Flint