simplify includes prereq/req order:

- everything that has prereq will also do includes, add it late, so that
gnu stuff (the only part with prereq) happens late.
- new RUN_MAKE snippet, to be able to have the makefile magically decide
between Makefile.bsd-wrapper and Makefile.
So there's no longer any need to remember complicated rules: add it to
RDIRS if it just wants make includes, add it to PRDIRS if it wants prereq too,
and that's all.
okay deraadt@, miod@

src/include/Makefile

@@ -1,4 +1,4 @@
-#	$OpenBSD: Makefile,v 1.162 2012/04/22 23:43:38 espie Exp $
+#	$OpenBSD: Makefile,v 1.163 2012/06/19 17:15:02 espie Exp $
 #	$NetBSD: Makefile,v 1.59 1996/05/15 21:36:43 jtc Exp $
 
 #	@(#)Makefile	5.45.1.1 (Berkeley) 5/6/91
@@ -37,6 +37,9 @@ DIRS=	arpa protocols rpc rpcsvc
 LDIRS=	altq crypto ddb dev isofs miscfs msdosfs net netinet netinet6 \
 	netmpls netnatm net80211 netbt nfs nnpfs ntfs scsi sys ufs uvm
 
+# Places that need a prerequisite target met before includes
+PRDIRS=
+
 # Directories with an includes target
 RDIRS=	../lib/libpthread ../lib/libcompat ../lib/libcurses \
 	../lib/libform ../lib/libssl ../lib/libmenu \
@@ -46,30 +49,23 @@ RDIRS=	../lib/libpthread ../lib/libcompat ../lib/libcurses \
 	../lib/libwrap \
 	../lib/libz ../lib/libkeynote ../lib/libevent ../usr.bin/lex \
 	../gnu/lib/libreadline ../gnu/usr.sbin/sendmail/libmilter \
-	../sys/arch/${MACHINE}
-
-# Places using Makefile that needs a prerequisite target met before includes
-PRDIRS=
-
-# Directories with an includes target that use Makefile.bsd-wrapper
-WDIRS=	../usr.sbin/httpd
-
-# Places using Makefile.bsd-wrapper that needs a prerequisite target met
-# before includes
-PWDIRS=
+	../sys/arch/${MACHINE} ../usr.sbin/httpd
 
 .if ${COMPILER_VERSION:L} == "gcc3" 
-WDIRS+= ../gnu/lib/libstdc++ ../gnu/usr.bin/gcc ../gnu/lib/libobjc
-PWDIRS+= ../gnu/lib/libstdc++
+RDIRS+= ../gnu/usr.bin/gcc ../gnu/lib/libobjc
+PRDIRS+= ../gnu/lib/libstdc++
 .elif ${COMPILER_VERSION:L} == "gcc4"
-RDIRS+= ../gnu/lib/libstdc++-v3 ../gnu/usr.bin/cc/libobjc
+RDIRS+= ../gnu/usr.bin/cc/libobjc
 PRDIRS+= ../gnu/lib/libstdc++-v3
 RDIRS+= ../gnu/usr.bin/cc/include
 .else
-WDIRS+= ../gnu/egcs/libio ../gnu/egcs/libstdc++ \
+RDIRS+= ../gnu/egcs/libio ../gnu/egcs/libstdc++ \
 	../gnu/lib/libobjc ../gnu/egcs/gcc
 .endif
 
+# prereq implies includes
+RDIRS += ${PRDIRS}
+
 NOOBJ=	noobj
 
 # Change SYS_INCLUDE in bsd.own.mk to "symlinks" if you don't want copies
@@ -78,14 +74,12 @@ SYS_INCLUDE?=	copies
 RDIRS+= ../lib/libkrb5 ../lib/libgssapi ../lib/libkadm5srv
 .endif
 
+RUN_MAKE = if test -f Makefile.bsd-wrapper; then ${MAKE} -f Makefile.bsd-wrapper $@; else ${MAKE} $@; fi
+
 prereq:
 	@for i in ${PRDIRS}; do \
 		echo preparing in ${.CURDIR}/$$i; \
-		cd ${.CURDIR}/$$i && ${MAKE} prereq; \
-	done
-	@for i in ${PWDIRS}; do \
-		echo preparing in ${.CURDIR}/$$i; \
-		cd ${.CURDIR}/$$i && ${MAKE} -f Makefile.bsd-wrapper prereq; \
+		cd ${.CURDIR}/$$i && ${RUN_MAKE}; \
 	done
 
 includes:
@@ -125,11 +119,7 @@ includes:
 		xargs -0r chmod u=rwx,go=rx
 	@for i in ${RDIRS}; do \
 		echo installing in ${.CURDIR}/$$i; \
-		cd ${.CURDIR}/$$i && ${MAKE} includes; \
-	done
-	@for i in ${WDIRS}; do \
-		echo installing in ${.CURDIR}/$$i; \
-		cd ${.CURDIR}/$$i && ${MAKE} -f Makefile.bsd-wrapper includes; \
+		cd ${.CURDIR}/$$i && ${RUN_MAKE}; \
 	done
 
 copies: