Introduce the new mk internal target _includeinstall and add the

controlling knob defaults INCOWN, INCGRP, INCMODE, and INCDIR.

Reviewed by:	marcel, and make world

share/mk/bsd.lib.mk

@@ -259,7 +259,17 @@ _EXTRADEPEND:
 
 .if !target(install)
 .if !target(beforeinstall)
-beforeinstall:
+beforeinstall: _includeinstall
+.endif
+
+_includeinstall:
+.if defined(INCS)
+.for header in ${INCS}
+	cd ${.CURDIR} && \
+	${INSTALL} -C -o ${INCOWN} -g ${INCGRP} -m ${INCMODE} \
+		${header} ${DESTDIR}${INCDIR}
+
+.endfor
 .endif
 
 .if defined(PRECIOUSLIB) && !defined(NOFSCHG)

share/mk/bsd.own.mk

@@ -39,6 +39,13 @@
 #
 # NOBINMODE	Mode for non-executable files. [444]
 #
+# INCOWN	Include owner. [root]
+#
+# INCGRP	Include group. [wheel]
+#
+# INCMODE	Include mode. [444]
+#
+# INCDIR	Base path for include files. [/usr/include]
 #
 # LIBDIR	Base path for libraries. [/usr/lib]
 #
@@ -141,6 +148,11 @@ NOBINMODE?=	444
 
 GAMEGRP?=	games
 
+INCOWN?=	root
+INCGRP?=	wheel
+INCMODE?=	444
+INCDIR?=	/usr/include
+
 KMODDIR?=	/modules
 KMODOWN?=	${BINOWN}
 KMODGRP?=	${BINGRP}