Acutally, replaces NO_INCS with WITHOUT_INCLUDES and make

WITHOUT_TOOLCHAIN imply it instead.

Sponsored by: Netflix

share/mk/bsd.incs.mk

@@ -4,7 +4,7 @@
 .error bsd.incs.mk cannot be included directly.
 .endif
 
-.if ${MK_TOOLCHAIN} != "no"
+.if ${MK_INCLUDES} != "no"
 
 INCSGROUPS?=	INCS
 

share/mk/bsd.opts.mk

@@ -51,6 +51,7 @@ __<bsd.opts.mk>__:
 __DEFAULT_YES_OPTIONS = \
     ASSERT_DEBUG \
     DOCCOMPRESS \
+    INCLUDES \
     INSTALLLIB \
     KERBEROS \
     MAN \

share/mk/src.opts.mk

@@ -306,6 +306,7 @@ MK_BINUTILS:=	no
 MK_CLANG:=	no
 MK_GCC:=	no
 MK_GDB:=	no
+MK_INCLUDES:=	no
 .endif
 
 .if ${MK_CLANG} == "no"

tools/build/options/WITHOUT_INCLUDES

@@ -0,0 +1,8 @@
+.\" $FreeBSD$
+Set to not install header files.
+This option used to be spelled 
+.Va NO_INCS .
+.Bf -symbolic
+The option does not work for build targets.
+.Ef
+