Look for our header files first, then for systems headers.

diff --git a/Make.rules.in b/Make.rules.in
index a90115a..ce878a8 100644
--- a/Make.rules.in
+++ b/Make.rules.in
@@ -33,7 +33,7 @@
 RANLIB    = @RANLIB@
 LN_S      = @LN_S@
 DIVINCL   = -I$(SRCDIR) -I. -I$(TOPSRCDIR)/include -I$(TOPOBJDIR)/include
-ALLCFLAGS = $(CFLAGS) $(DEFS) $(OPTIONS) $(DIVINCL) $(X_CFLAGS)
+ALLCFLAGS = $(DIVINCL) $(CFLAGS) $(DEFS) $(OPTIONS) $(X_CFLAGS)
 LDCOMBINE = ld -r
 LDSHARED  = @LDSHARED@
 AR        = ar rc