lei: prefer IO::FDPass over our Inline::C recv_3fds

While our recv_3fds() implementation is more efficient
syscall-wise, loading Inline takes nearly 50ms on my machine
even after Inline::C memoizes the build.  The current ~20ms in
the fast path is barely acceptable to me, and 50ms would be
unusable.

Eventually, script/lei may invoke tcc(1) or cc(1) directly in
the fast path, but it needs @INC for the slow path, at least.

We'll encode the number of FDs into the socket name allow
parallel installations, for now.

1 files changed, 6 insertions, 4 deletions

diff --git a/t/lei.t b/t/lei.t
index 42c0eb8f..5afb8351 100644
--- a/t/lei.t
+++ b/t/lei.t
@@ -193,12 +193,14 @@ if ($ENV{TEST_LEI_ONESHOT}) {
 
 SKIP: { # real socket
         require_mods(qw(Cwd), my $nr = 46);
-        require PublicInbox::Spawn;
-        skip "Inline::C not installed/configured or IO::FDPass missing", $nr
-                unless PublicInbox::Spawn->can('send_3fds');
+        my $nfd = eval { require IO::FDPass; 1 } // do {
+                require PublicInbox::Spawn;
+                PublicInbox::Spawn->can('send_3fds') ? 3 : undef;
+        } //
+        skip 'IO::FDPass missing or Inline::C not installed/configured', $nr;
 
         local $ENV{XDG_RUNTIME_DIR} = "$home/xdg_run";
-        my $sock = "$ENV{XDG_RUNTIME_DIR}/lei/sock";
+        my $sock = "$ENV{XDG_RUNTIME_DIR}/lei/$nfd.sock";
 
         ok($lei->('daemon-pid'), 'daemon-pid');
         is($err, '', 'no error from daemon-pid');