Add "-I@/../include" and/or "-I${DESTDIR}/usr/include" to CFLAGS,

essentially as in kernel makefiles, so that module sources can include
<stddef.h> and other standard headers.  Only add the second path when
the first path can't be found, instead of when DESTDIR is defined.
Adding it used to be just an obfuscation.

Use "${.OBJDIR}" instyead of "." in -I paths.  Using "${.OBJDIR}" just
gave more verbose command lines and depend files.

1 files changed, 12 insertions, 3 deletions

diff --git a/share/mk/bsd.kmod.mk b/share/mk/bsd.kmod.mk
index bc5aa9947524..300d17ad8c1f 100644
--- a/share/mk/bsd.kmod.mk
+++ b/share/mk/bsd.kmod.mk
@@ -102,12 +102,21 @@ CFLAGS+=	-nostdinc -I- ${_ICFLAGS}
 # Add -I paths for system headers.  Individual KLD makefiles don't
 # need any -I paths for this.  Similar defaults for .PATH can't be
 # set because there are no standard paths for non-headers.
-CFLAGS+=	-I${.OBJDIR} -I${.OBJDIR}/@
+CFLAGS+=	-I. -I@
 
-# XXX this is now dubious.
-.if defined(DESTDIR)
+# Add a -I path to standard headers like <stddef.h>.  Use a relative
+# path to src/include if possible.  If the @ symlink hasn't been built
+# yet, then we can't tell if the relative path exists.  Add both the
+# potential relative path and an absolute path in that case.
+.if exists(@)
+.if exists(@/../include)
+CFLAGS+=	-I@/../include
+.else
 CFLAGS+=	-I${DESTDIR}/usr/include
 .endif
+.else # !@
+CFLAGS+=	-I@/../include -I${DESTDIR}/usr/include
+.endif # @
 
 .if ${OBJFORMAT} == elf
 CLEANFILES+=	setdef0.c setdef1.c setdefs.h