From 971a81944643103a5e6183c8017fa9306bc76c7a Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@aps.anl.gov>
Date: Wed, 4 Feb 2015 16:28:23 -0600
Subject: [PATCH] Use order-only prerequisites for include files

This prevents unnecessary recompilations when an include
file gets regenerated.
---
 configure/RULES_BUILD | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/configure/RULES_BUILD b/configure/RULES_BUILD
index 31267faf9..2c0cb7bdf 100644
--- a/configure/RULES_BUILD
+++ b/configure/RULES_BUILD
@@ -215,15 +215,16 @@ $(TESTPRODNAME) $(PRODNAME): %$(EXE):
 %.o : %.cc
 %.o : %.cpp
 
-%$(OBJ): %.c $(COMMON_INC) $(INSTALL_INC)
+# Include files are order-only prerequisites for compilation:
+%$(OBJ): %.c | $(COMMON_INC) $(INSTALL_INC)
 	@$(RM) $@
 	$(COMPILE.c) -c $<
 
-%$(OBJ): %.cc $(COMMON_INC) $(INSTALL_INC)
+%$(OBJ): %.cc | $(COMMON_INC) $(INSTALL_INC)
 	@$(RM) $@
 	$(COMPILE.cpp) -c $<
 
-%$(OBJ): %.cpp $(COMMON_INC) $(INSTALL_INC)
+%$(OBJ): %.cpp | $(COMMON_INC) $(INSTALL_INC)
 	@$(RM) $@
 	$(COMPILE.cpp) -c $<