Implement symbol visibility.
* configure.ac: New option --enable-ld-version-script. (GPGRT_USE_VISIBILITY): New ac_define. (HAVE_LD_VERSION_SCRIPT): New am_conditional. * src/gpg-error.vers: New. * src/gpgrt-int.h: New. * src/visibility.c, src/visibility.h: New. Lot of changes to symbold names.
This is only doe for the old API. The estream API needs to be added.