_SUBDIR is marked .MAKE - since it runs a sub-make.

Targets thus marked are supposed to run even with -n.
As such they should not do anything except run the sub-make.

Use an intermediate target _* to associate with _SUBDIR and which
depends on installincludes etc so that we get the correct behavior with -n.

Reviewed by:	marcel

share/mk/bsd.subdir.mk

@@ -104,8 +104,9 @@ ${__target}: _SUBDIR
 .for __target in files includes
 .for __stage in build install
 ${__stage}${__target}:
+_${__stage}${__target}: ${__stage}${__target}
 .if make(${__stage}${__target})
-${__stage}${__target}: _SUBDIR
+_${__stage}${__target}: _SUBDIR
 .endif
 .endfor
 ${__target}: .MAKE