build: fix bundled libcurl and c-ares build on OS X

c-ares relies on libresolv on OS X, and when built statically, brings
the same dependency on to libcurl.

Link libcurl with libresolv explicitly when linking with c-ares

NO_DOC=build fix
NO_TEST=build fix
NO_CHANGELOG=build fix

cmake/BuildLibCURL.cmake

@@ -230,6 +230,9 @@ macro(curl_build)
     set(CURL_LIBRARIES bundled-libcurl ${ZLIB_LIBRARIES})
     if (BUNDLED_LIBCURL_USE_ARES)
         set(CURL_LIBRARIES ${CURL_LIBRARIES} ${ARES_LIBRARIES})
+        if (TARGET_OS_DARWIN)
+            set(CURL_LIBRARIES ${CURL_LIBRARIES} resolv)
+        endif()
     endif()
     if (BUNDLED_LIBCURL_USE_NGHTTP2)
         set(CURL_LIBRARIES ${CURL_LIBRARIES} ${NGHTTP2_LIBRARIES})