maint: ignore all *.out in .gitignore.

* .gitignore (*.out): ignore all at top level; common temp files.
diff --git a/.gitignore b/.gitignore
index 40540ad..d1606f2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,5 @@
 *~
+*.out
 .#*
 .*.sw[op]
 \#*#
@@ -66,7 +67,4 @@
 /test-suite.log
 TAGS
 cscope.files
-cscope.in.out
-cscope.out
-cscope.po.out
 tags