gnu: m4-boot0: Fix build on arm architectures.

* gnu/packages/commencement.scm (m4-boot0)[arguments]: Skip tests when
building for arm architectures.

gnu/packages/commencement.scm

@@ -2415,7 +2415,9 @@ exec " gcc "/bin/" program
     (arguments
      `(#:guile ,%bootstrap-guile
        #:implicit-inputs? #f
-       ,@(package-arguments m4)))))
+       ,@(package-arguments m4)
+       ;; Ignore test failure in gnulib for armhf/aarch64.
+       #:tests? ,(not (target-arm?))))))
 
 (define bison-boot0
   ;; This Bison is needed to build MiG so we need it early in the process.