gnu: make-gcc-toolchain: Add gcc:lib.

* gnu/packages/commencement.scm (make-gcc-toolchain)[inputs]: Add gcc:lib.

Change-Id: I327a2403d5d14dd545981e8e9dbfd7df24c9357e

gnu/packages/commencement.scm

@@ -3612,6 +3612,7 @@ is the GNU Compiler Collection.")
                 ("ld-wrapper" ,(car (assoc-ref (%final-inputs (%current-system))
                                                "ld-wrapper")))
                 ("binutils" ,binutils-final)
+                ("gcc-lib" ,gcc "lib")
                 ("libc" ,libc)
                 ("libc-debug" ,libc "debug")
                 ("libc-static" ,libc "static"))))))