runit: Enable cross-compilation

pkgs/tools/system/runit/default.nix

@@ -13,6 +13,10 @@ stdenv.mkDerivation rec {
     sha256 = "065s8w62r6chjjs6m9hapcagy33m75nlnxb69vg0f4ngn061dl3g";
   };
 
+  patches = [
+    ./fix-ar-ranlib.patch
+  ];
+
   outputs = [ "out" "man" ];
 
   sourceRoot = "admin/${name}";
@@ -34,8 +38,8 @@ stdenv.mkDerivation rec {
     cd src
 
     # Both of these are originally hard-coded to gcc
-    echo cc > conf-cc
-    echo cc > conf-ld
+    echo ${stdenv.cc.targetPrefix}cc > conf-cc
+    echo ${stdenv.cc.targetPrefix}cc > conf-ld
   '';
 
   installPhase = ''

pkgs/tools/system/runit/fix-ar-ranlib.patch

@@ -0,0 +1,18 @@
+--- runit-2.1.2/src/print-ar.sh
++++ runit-2.1.2/src/print-ar.sh
+@@ -1,7 +1,7 @@
+ cat warn-auto.sh
+ echo 'main="$1"; shift'
+ echo 'rm -f "$main"'
+-echo 'ar cr "$main" ${1+"$@"}'
++echo '$AR cr "$main" ${1+"$@"}'
+ case "`cat systype`" in
+   sunos-5.*) ;;
+   unix_sv*) ;;
+@@ -10,5 +10,5 @@ case "`cat systype`" in
+   dgux-*) ;;
+   hp-ux-*) ;;
+   sco*) ;;
+-  *) echo 'ranlib "$main"' ;;
++  *) echo '$RANLIB "$main"' ;;
+ esac