allow pkg-config in case of vcpkg fail

so MinGW can also have an ability to link system libcurl

Author: ognevny

curl-sys/build.rs

@@ -40,7 +40,9 @@ fn main() {
             if try_vcpkg() {
                 return;
             }
-        } else if try_pkg_config() {
+        }
+
+        if try_pkg_config() {
             return;
         }
     }