minimal-bootstrap.musl: parallelise build

pkgs/os-specific/linux/minimal-bootstrap/default.nix

@@ -140,6 +140,7 @@ lib.makeScope
 
     musl = callPackage ./musl {
       gcc = gcc46;
+      gnumake = gnumake-musl;
     };
 
     stage0-posix = callPackage ./stage0-posix { };

pkgs/os-specific/linux/minimal-bootstrap/musl/default.nix

@@ -70,8 +70,8 @@ bash.runCommand "${pname}-${version}" {
     --host=${hostPlatform.config}
 
   # Build
-  make
+  make -j $NIX_BUILD_CORES
 
   # Install
-  make install
+  make -j $NIX_BUILD_CORES install
 ''