Contribs: fix GnuTLS linking on Win32

(cherry picked from commit d53688897ec773695def279cea2a179d5620c4e9)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

contrib/src/gnutls/gnutls-win32.patch

@@ -15,3 +15,13 @@
  # endif
 +#endif
  #endif /* !HAVE_DECL_GAI_STRERROR */
+--- gnutls-3.2.17/lib/gnutls.pc.in.orig	2014-08-30 06:48:22.371307704 +0200
++++ gnutls-3.2.17/lib/gnutls.pc.in	2014-08-30 06:48:40.504956268 +0200
+@@ -19,6 +19,6 @@
+ URL: http://www.gnutls.org/
+ Version: @VERSION@
+ Libs: -L${libdir} -lgnutls
+-Libs.private: @LTLIBZ@ @LTLIBINTL@ @LIBSOCKET@ @LTLIBPTHREAD@ @LTLIBICONV@ @P11_KIT_LIBS@ @LIB_SELECT@ @TSS_LIBS@ @GMP_LIBS@
++Libs.private: @LTLIBZ@ @LTLIBINTL@ @LIBSOCKET@ -lcrypt32 @LTLIBPTHREAD@ @LTLIBICONV@ @P11_KIT_LIBS@ @LIB_SELECT@ @TSS_LIBS@ @GMP_LIBS@
+ @GNUTLS_REQUIRES_PRIVATE@
+ Cflags: -I${includedir}