w32: Support static link with -lws2_32.
* configure.ac (GPG_ERROR_CONFIG_LIBS_PRIVATE): New. * src/Makefile.am (socklibs): Use GPG_ERROR_CONFIG_LIBS_PRIVATE. * src/gpg-error.pc.in: Require @GPG_ERROR_CONFIG_LIBS_PRIVATE@.
- GnuPG-bug-id: T4623
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>