config: git_config_dump: pre-compile RE for split

It appears the Perl split() operator is not optimized for fixed
strings at all.  With this change, PublicInbox::Config->new (w/o
->fill_all) time is reduced from 1.81s to 1.22s on a config file
with 50K inboxes.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index cd8957a1..4d143c6e 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -165,7 +165,7 @@ sub git_config_dump {
         return {} unless -e $file;
         my $cmd = [ qw(git config -z -l --includes), "--file=$file" ];
         my $fh = popen_rd($cmd);
-        my $rv = config_fh_parse($fh, "\0", "\n");
+        my $rv = config_fh_parse($fh, "\0", qr/\n/);
         close $fh or die "failed to close (@$cmd) pipe: $?";
         $rv;
 }