Support building CMake packages for additional gpgex architecture
* configure.ac: Generate src/toolchain-ex.cmake. * m4/gpg4win.m4: Add function GPG4WIN_CMKPKGEX. * src/Makefile.am: Add variable gpg4win_excmkpkgs. * src/gpg4win.mk.in: Define EXCMKPKG_template_ and EXCMKPKG_template. Call EXCMKPKG_template for each value in gpg4win_excmkpkgs. * src/toolchain-ex.cmake.in: New.
This makes it possible to build CMake packages (like gpgmepp) for the
additional gpgex architecture (i.e. 64 bit).
- GnuPG-bug-id: T7262