Add in missing dependency for windows builds.

Commit f95272d created some undefined references in GnuTLS.
diff --git a/cmake/StaticBuild.cmake b/cmake/StaticBuild.cmake
index 4ef2905..5800a07 100644
--- a/cmake/StaticBuild.cmake
+++ b/cmake/StaticBuild.cmake
@@ -34,7 +34,7 @@
     set(GNUTLS_LIBRARIES "-Wl,-Bstatic -lgnutls -ltasn1")
 
     if(NETTLE_LIBRARY)
-      set(GNUTLS_LIBRARIES "${GNUTLS_LIBRARIES} -lnettle -lhogweed -lgmp")
+      set(GNUTLS_LIBRARIES "${GNUTLS_LIBRARIES} -lnettle -lhogweed -lgmp -lcrypt32")
     endif()
     if(GCRYPT_LIBRARY)
       set(GNUTLS_LIBRARIES "${GNUTLS_LIBRARIES} -lgcrypt -lgpg-error")