Stop make deleting intermediate files (ffmpeg.o and friends)

Originally committed as revision 22094 to svn://svn.ffmpeg.org/ffmpeg/trunk

common.mak

@@ -55,6 +55,9 @@ uninstall: uninstall-libs uninstall-headers
 # Disable suffix rules.  Most of the builtin rules are suffix rules,
 # so this saves some time on slow systems.
 .SUFFIXES:
+
+# Do not delete intermediate files from chains of implicit rules
+.SECONDARY:
 endif
 
 OBJS-$(HAVE_MMX) +=  $(MMX-OBJS-yes)