APACHE_CHECK_CURL: Cache MOD_CFLAGS and MOD_LDFLAGS a2md reuses the result from checking for mod_md. Idea taken from APACHE_CHECK_OPENSSL and APACHE_CHECK_JANSSON. git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1938437 13f79535-47bb-0310-9956-ffa450edef68