Adding zlib to GCC

[Anthony Green <green at cygnus dot com>]

Hello -

	One of the most common forms of Java "source" files are compressed bytecode 
archives.  gcj can currently extract bytecode from un-compressed archives, 
but for the most part they're all compressed, and this is one of the most 
common complaints about gcj.

	I have a simple patch to gcj which lets is read class files from compressed 
archives, but it uses zlib.  Zlib is already part of libgcj, and we intend to 
check this in anyway when we add libgcj to the GCC source tree.  Zlib, as it 
exists in libgcj, is built with autoconf/automake/libtool.  What Tom Tromey 
and I discussed was moving the ,v files for zlib from the libgcj tree over to 
GCC.  Like libiberty, it would eventually have to build as both a host and 
target library (when the rest of libgcj gets imported).

	libgcj has a configure option --with-system-zlib which we would also move 
over to GCC.  This would link the program against the system's libz.so, and 
might be used by OS packagers.  It's probably unsuitable for general use 
because we rely on a commonly used, yet undocumented feature of zlib to read 
headerless archive entries.

	I believe there is general agreement among the maintainers that libgcj will 
move into the GCC sources, and zlib is part of libgcj, but now we're talking 
about using zlib to build the compiler.  Any objections to this plan?

Thanks,

AG