gnu: earlyoom: Only build with pandoc on certain systems.

* gnu/packages/linux.scm (earlyoom)[native-inputs]: Only use pandoc on
x86_64-linux and i686-linux.

gnu/packages/linux.scm

@@ -3756,12 +3756,15 @@ from the module-init-tools project.")
                "GO111MODULE=off")
        #:test-target "test"))
     (native-inputs
+      (append
+        ;; To generate the manpage.
+        (if (or (target-x86-64?) (target-x86-32?))
+          (list pandoc)
+          '())
         (list
           ;; For the test suite.
           cppcheck
-        go
-        ;; To generate the manpage.
-        pandoc))
+          go)))
     (home-page "https://github.com/rfjakob/earlyoom")
     (synopsis "Simple out of memory (OOM) daemon for the Linux kernel")
     (description "Early OOM is a minimalist out of memory (OOM) daemon that