Improve libgdiplus path handling

Since libgdiplus is not installed together with Mono, it should not be
assumed to be in the same prefix.

The new policy for the --with-libgdiplus configure option is the
following:

 - --with-libgdiplus=/absolute/path/to/libgdiplus.{so,dylib}

   both during build/check and after installation Mono will try to use
   the specified libgdiplus library; the rationale is that when an
   absolute path is given, it can be assumed to be the full path to
   the library that is already installed (possibly in a non-default
   path).

 - default, --with-libgdiplus=no, --with-libgdiplus=installed

   both during build/check and after installation Mono will try to use
   a system-wide libgdiplus library, that is assumed to reside in the
   paths that are automatically searched by the dynamic linker; the
   library is supposed to be already installed in the default path and
   to be useable both during the build and afterwards.

 - --with-libgdiplus=sibling, --with-libgdiplus=yes

   during build/check Mono will try to use the libgdiplus library that
   is assumed to be in the sibling folder (../libgdiplus), but after
   the installation it will try to use a system-wide libgdiplus
   library, that should be in the paths that are automatically
   searched by the dynamic linker; the assumption is that the library
   is not yet installed, but it will go to the default prefix after
   installing it.

 - --with-libgdiplus=../some/relative/path/to/libgdiplus.{so,dylib,la}

   during build/check Mono will try to use the specified libgdiplus
   library, but after the installation it will try to use a
   system-wide libgdiplus library, that should be in the paths that
   are automatically searched by the dynamic linker; the assumption is
   that the library is not yet installed, but it will go to the
   default prefix after installing it.

0 files changed, 0 insertions, 0 deletions