Make jam print the commandline it's executing.
Only useful for ebuild debugging - I just always forget how to enable it.

--- ftjam-2.5.3rc2-orig/builds/unix/Makefile.in
+++ ftjam-2.5.3rc2/builds/unix/Makefile.in
@@ -16,7 +16,7 @@
 
 all: jam0
 	chmod a+w jambase.c
-	./jam0
+	./jam0 -dx -q
 
 include common.mk
 
