diff --git a/GNUmakefile b/GNUmakefile
index e32161d7..18a1fecd 100644
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -1,4 +1,4 @@
-# $Id: GNUmakefile,v 1.72 2009-02-18 08:41:22 nicm Exp $
+# $Id: GNUmakefile,v 1.73 2009-02-18 08:50:30 nicm Exp $
 
 .PHONY: clean
 
@@ -46,7 +46,7 @@ SRCS= tmux.c server.c server-msg.c server-fn.c buffer.c buffer-poll.c status.c \
       osdep-darwin.c attributes.c
 
 CC?= gcc
-CPPFLAGS+= -I. -I-
+INCDIRS+= -I. -I-
 CFLAGS+= -DBUILD="\"$(VERSION) ($(DATE))\"" -DMETA="'${META}'"
 ifdef FDEBUG
 CFLAGS+= -g -ggdb -DDEBUG
@@ -68,7 +68,7 @@ INSTALLBIN= install -g bin -o root -m 555
 INSTALLMAN= install -g bin -o root -m 444
 
 ifeq ($(shell uname),IRIX64)
-CPPFLAGS+= -Icompat -I/usr/local/include/ncurses
+INCDIRS+= -Icompat -I/usr/local/include/ncurses
 SRCS+= compat/strlcpy.c compat/strtonum.c compat/daemon.c \
 	compat/asprintf.c compat/fgetln.c compat/forkpty-irix.c
 CFLAGS+= -DNO_STRLCPY -DNO_STRTONUM -DNO_TREE_H -DNO_SETPROCTITLE \
@@ -79,7 +79,7 @@ LIBS+= -lgen
 endif
 
 ifeq ($(shell uname),SunOS)
-CPPFLAGS+= -Icompat -I/usr/local/include/ncurses
+INCDIRS+= -Icompat -I/usr/local/include/ncurses
 SRCS+= compat/strtonum.c compat/daemon.c compat/forkpty-sunos.c \
 	compat/asprintf.c compat/fgetln.c compat/vis.c
 CFLAGS+= -DNO_STRTONUM -DNO_TREE_H -DNO_PATHS_H -DNO_SETPROCTITLE \
@@ -89,14 +89,14 @@ LIBS+= -lsocket -lnsl
 endif
 
 ifeq ($(shell uname),Darwin)
-CPPFLAGS+= -Icompat
+INCDIRS+= -Icompat
 SRCS+= compat/strtonum.c compat/bsd-poll.c compat/vis.c
 CFLAGS+= -DNO_STRTONUM -DNO_SETRESUID -DNO_SETRESGID -DNO_SETPROCTITLE \
          -DNO_QUEUE_H -DNO_TREE_H -DBROKEN_POLL
 endif
 
 ifeq ($(shell uname),Linux)
-CPPFLAGS+= -Icompat
+INCDIRS+= -Icompat
 SRCS+= compat/strlcpy.c compat/strlcat.c compat/strtonum.c \
        compat/fgetln.c compat/getopt_long.c compat/vis.c
 CFLAGS+= $(shell getconf LFS_CFLAGS) -D_GNU_SOURCE \
@@ -110,6 +110,8 @@ OBJS= $(patsubst %.c,%.o,$(SRCS))
 
 CLEANFILES= ${PROG} *.o .depend *~ ${PROG}.core *.log compat/*.o index.html
 
+CPPFLAGS:= ${INCDIRS} ${CPPFLAGS}
+
 all: $(PROG)
 
 $(PROG): $(OBJS)
diff --git a/Makefile b/Makefile
index 661232cb..5e762dc9 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-# $Id: Makefile,v 1.113 2009-02-18 08:41:22 nicm Exp $
+# $Id: Makefile,v 1.114 2009-02-18 08:50:30 nicm Exp $
 
 .SUFFIXES: .c .o .y .h
 .PHONY: clean update-index.html upload-index.html
@@ -48,8 +48,8 @@ SRCS= tmux.c server.c server-msg.c server-fn.c buffer.c buffer-poll.c status.c \
       osdep-unknown.c osdep-openbsd.c osdep-freebsd.c osdep-linux.c \
       osdep-darwin.c osdep-netbsd.c
 
-CC?= cc
-CPPFLAGS+= -I. -I- -I/usr/local/include
+CC?= c
+INCDIRS+= -I. -I- -I/usr/local/include
 CFLAGS+= -DMETA="'${META}'"
 .ifdef PROFILE
 # Don't use ccache
@@ -82,7 +82,7 @@ LIBS+= -lutil -lncurses
 
 # FreeBSD and DragonFly
 .if ${OS} == "FreeBSD" || ${OS} == "DragonFly"
-CPPFLAGS+= -Icompat
+INCDIRS+= -Icompat
 SRCS+= compat/vis.c
 CFLAGS+= -DUSE_LIBUTIL_H -DNO_QUEUE_H -DNO_TREE_H
 LIBS+= -lcrypt
@@ -90,7 +90,7 @@ LIBS+= -lcrypt
 
 # NetBSD
 .if ${OS} == "NetBSD"
-CPPFLAGS= -Icompat
+INCDIRS= -Icompat
 SRCS+= compat/strtonum.c compat/vis.c
 LIBS+= -lcrypt
 CFLAGS+=-DNO_STRTONUM
@@ -104,6 +104,8 @@ DISTFILES= *.[chyl] Makefile GNUmakefile *.[1-9] NOTES TODO CHANGES FAQ \
 
 CLEANFILES= ${PROG} *.o .depend *~ ${PROG}.core *.log compat/*.o index.html
 
+CPPFLAGS:= ${INCDIRS} ${CPPFLAGS} 
+
 .c.o:
 		${CC} ${CPPFLAGS} ${CFLAGS} -c ${.IMPSRC} -o ${.TARGET}