contrib: freetype: actually disable bzip2

Regression from d9c9482b.

This fixes linking on macOS with static Qt from contribs:

Undefined symbols for architecture x86_64:
  "_BZ2_bzDecompress", referenced from:
      _ft_bzip2_file_fill_output in libfreetype.a(ftbzip2.c.o)
  "_BZ2_bzDecompressEnd", referenced from:
      _ft_bzip2_stream_io in libfreetype.a(ftbzip2.c.o)
      _ft_bzip2_stream_close in libfreetype.a(ftbzip2.c.o)
  "_BZ2_bzDecompressInit", referenced from:
      _FT_Stream_OpenBzip2 in libfreetype.a(ftbzip2.c.o)
      _ft_bzip2_stream_io in libfreetype.a(ftbzip2.c.o)
ld: symbol(s) not found for architecture x86_64

contrib/src/freetype2/rules.mak

@@ -20,7 +20,7 @@ freetype: freetype-$(FREETYPE2_VERSION).tar.xz .sum-freetype2
 
 DEPS_freetype2 = zlib $(DEPS_zlib)
 
-FREETYPE_CONF = -DFT_DISABLE_ZLIB=OFF -DFT_DISABLE_PNG=ON -DFT_DISABLE_BZIP2=NO \
+FREETYPE_CONF = -DFT_DISABLE_ZLIB=OFF -DFT_DISABLE_PNG=ON -DFT_DISABLE_BZIP2=ON \
                 -DDISABLE_FORCE_DEBUG_POSTFIX:BOOL=ON -DFT_DISABLE_HARFBUZZ=ON \
                 -DFT_DISABLE_BROTLI=ON