help management of empty pkg and lib directories in perforce

R=gri
DELTA=4  (4 added, 0 deleted, 0 changed)
OCL=13328
CL=13328

lib/place-holder

diff --git a/lib/place-holder b/lib/place-holder
new file mode 100644
index 0000000..aa084c8
--- /dev/null
+++ b/lib/place-holder
@@ -0,0 +1,2 @@
+perforce does not maintain empty directories.
+this file helps.

pkg/place-holder

diff --git a/pkg/place-holder b/pkg/place-holder
new file mode 100644
index 0000000..aa084c8
--- /dev/null
+++ b/pkg/place-holder
@@ -0,0 +1,2 @@
+perforce does not maintain empty directories.
+this file helps.

src/cmd/gc/mksys.bash

diff --git a/src/cmd/gc/mksys.bash b/src/cmd/gc/mksys.bash
old mode 100644
new mode 100755