include/Makefile: mark serno.h as phony to force it to be regenerated every time

Rylai · Rylai · commit bf297a1e902d · 2014-01-17T12:21:51.000-05:00
this is desired behavior as a "make distclean" is not always run between git pulls.
diff --git a/include/Makefile b/include/Makefile
@@ -1,5 +1,7 @@
 include ../extra.mk
 
+.PHONY: serno.h
+
 SUBDIRS = inline protocol
 
 DISTCLEAN = hooktypes.h serno.h
