Cause an error during 'make install' if trying to compile with CC.

This is limited to src-tree builds, meaning not extended to ports or other
out-of-tree builds.

This will help ensure that read-only OBJDIRS will be respected at install-time
by causing a more consistent failure for those who don't use a read-only
OBJDIR.  It also will cause Jenkins to yell.  This is a better solution than
trying to see CC=false as has been attempted and discussed before.

Of course this is only relevant for files generated by CC.

Disable this for META_MODE since it will detect the CFLAGS/command
change and force a rebuild.

Sponsored by:	EMC / Isilon Storage Division

1 files changed, 7 insertions, 0 deletions

diff --git a/share/mk/bsd.sys.mk b/share/mk/bsd.sys.mk
index 5660bd4..709556e 100644
--- a/share/mk/bsd.sys.mk
+++ b/share/mk/bsd.sys.mk
@@ -178,6 +178,13 @@ ACFLAGS+=	${ACFLAGS.${.IMPSRC:T}}
 CFLAGS+=	${CFLAGS.${.IMPSRC:T}}
 CXXFLAGS+=	${CXXFLAGS.${.IMPSRC:T}}
 
+.if defined(SRCTOP)
+# Prevent rebuilding during install to support read-only objdirs.
+.if make(install) && empty(.MAKE.MODE:Mmeta)
+CFLAGS+=	ERROR-tried-to-rebuild-during-make-install
+.endif
+.endif
+
 # Tell bmake not to mistake standard targets for things to be searched for
 # or expect to ever be up-to-date.
 PHONY_NOTMAIN = analyze afterdepend afterinstall all beforedepend beforeinstall \