internal/rosa: chmod via patch helper

This works around the zfs overlay mount overhead and significantly reduces I/O in general.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/rosa/cmake.go

@@ -17,9 +17,6 @@ func (t Toolchain) newCMake() pkg.Artifact {
 		t.Load(Make),
 		t.Load(KernelHeaders),
 	}, nil, nil, `
-# expected to be writable in the copy made during bootstrap
-chmod -R +w /usr/src/cmake/Tests
-
 cd "$(mktemp -d)"
 /usr/src/cmake/bootstrap \
 	--prefix=/system \
@@ -28,13 +25,15 @@ cd "$(mktemp -d)"
 	-DCMAKE_USE_OPENSSL=OFF
 make "-j$(nproc)"
 make DESTDIR=/work install
-`, pkg.Path(AbsUsrSrc.Append("cmake"), true,
-		pkg.NewHTTPGetTar(
+`, pkg.Path(AbsUsrSrc.Append("cmake"), true, t.NewPatchedSource(
+		// expected to be writable in the copy made during bootstrap
+		"cmake", version, pkg.NewHTTPGetTar(
 			nil, "https://github.com/Kitware/CMake/releases/download/"+
 				"v"+version+"/cmake-"+version+".tar.gz",
 			mustDecode(checksum),
 			pkg.TarGzip,
-		)))
+		), false,
+	)))
 }
 func init() { artifactsF[CMake] = Toolchain.newCMake }