Add libtool patch to handle -Wl,--as-needed
This adds patches for Libtool to fix the handling of -Wl,--as-needed/-Wl,--no-as-needed
and -Wl,--whole-archive/-Wl,--no-whole-archive
(https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=347650).
We are mostly interested in the proper handling of -Wl,--as-needed
, which we rely on when building ICON. This patch will help get the shared version of a bundled library free from redundant dependencies meant for other bundled libraries.
This also updates contrib/00nagfor-libtool-patch/nagfor-libtool-2.4.2.patch
, which I could not apply without fixing the line numbers.