Update webkit2-gtk3 to 2.16.3.

• Fix the build when using port compile and binutils is installed. It seems Cmake picks up ar and ranlib from localbase when using a compiler from ports, but the compiler uses ld from base for linking. Base ld doesn't understand some features newer ar and ranlib from localbase are using. So tell the build to always use ar and ranlib from base. [1]
• Fix build failure on armv6 [2]

PR: 219161 [1], 219495 [2]
Submitted by: mikael.urankar@gmail.com [2]