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/perl.go

@@ -10,7 +10,7 @@ func (t Toolchain) newPerl() pkg.Artifact {
 	return t.New("perl-"+version, TEarly, []pkg.Artifact{
 		t.Load(Make),
 	}, nil, nil, `
-chmod -R +w /usr/src/perl && cd /usr/src/perl
+cd /usr/src/perl
 
 echo 'print STDOUT "1..0 # Skip broken test\n";' > ext/Pod-Html/t/htmldir3.t
 rm -f /system/bin/ps # perl does not like toybox ps
@@ -28,11 +28,12 @@ make \
 	TEST_JOBS=256 \
 	test_harness
 make DESTDIR=/work install
-`, pkg.Path(AbsUsrSrc.Append("perl"), true, pkg.NewHTTPGetTar(
-		nil,
-		"https://www.cpan.org/src/5.0/perl-"+version+".tar.gz",
-		mustDecode(checksum),
-		pkg.TarGzip,
+`, pkg.Path(AbsUsrSrc.Append("perl"), true, t.NewPatchedSource(
+		"perl", version, pkg.NewHTTPGetTar(
+			nil, "https://www.cpan.org/src/5.0/perl-"+version+".tar.gz",
+			mustDecode(checksum),
+			pkg.TarGzip,
+		), false,
 	)))
 }
 func init() { artifactsF[Perl] = Toolchain.newPerl }