gnu: webkitgtk: Disable SSE2 when not on x86_64.

* gnu/packages/webkit.scm (webkitgtk)[#:phases]: Add ‘disable-sse2’ if the
current (target) system is not an x86_64 one.

gnu/packages/webkit.scm

@@ -295,6 +295,13 @@ acceleration in mind, leveraging common 3D graphics APIs for best performance.")
                  (("libWPEBackend-fdo-([\\.0-9]+)\\.so" all version)
                   (string-append wpebackend-fdo "/lib/" all)))
                #t)))
+         ,@(if (string-prefix? "x86_64" (or (%current-target-system)
+                                            (%current-system)))
+               '()
+               '((add-after 'unpack 'disable-sse2
+                   (lambda _
+                     (substitute* "Source/cmake/DetectSSE2.cmake"
+                       (("CHECK_FOR_SSE2\\(\\)") ""))))))
          (add-before 'configure 'prepare-build-environment
            (lambda* (#:key inputs #:allow-other-keys)
              (setenv "CC" "clang")