X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=subdirmk%2Fcdeps.sd.mk;h=37ea60ff856f70b1339da87e997aaa3d31c34b3f;hb=16bce837ffe3527d4e8ed306f4436a86891d6e60;hp=5d58b6b90c979ccd5153a95aed7f1e007d3a0301;hpb=a2d0da0b0b2f40319d8787b98f5198f78303f85d;p=secnet.git

diff --git a/subdirmk/cdeps.sd.mk b/subdirmk/cdeps.sd.mk
index 5d58b6b..37ea60f 100644
--- a/subdirmk/cdeps.sd.mk
+++ b/subdirmk/cdeps.sd.mk
@@ -2,10 +2,25 @@
 #  Copyright 2019 Mark Wooding
 #  Copyright 2019 Ian Jackson
 # SPDX-License-Identifier: LGPL-2.0-or-later
+# There is NO WARRANTY.
+
+&# Usage:
+&#   &:include subdirmk/cdeps.sd.mk
+&# (probably in Suffix.sd.mk)
+&#
+&# Arranges for automatic #include dependency tracking for
+&# C compilation.  The compiler is asked to write the dependencies to
+&#  .*.d and these are automatically included.
+&#
+&# There is a bug: if a #included file is deleted and all references
+&# in .c files to it removed, `make' will complain that it is needed
+&# and can't be built.  `make clean' will fix this.
 
 CDEPS_CFLAGS ?= -MD -MF $(*D)/.$(*F).d
 
-&DEPFILES += $(foreach b,$(patsubst %.o,%,$(&OBJECTS)), \
+&CDEPS_OBJECTS += $(&OBJECTS)
+
+&DEPFILES += $(foreach b,$(patsubst %.o,%,$(&CDEPS_OBJECTS)), \
 		$(dir $b).$(notdir $b).d)
 -include $(&DEPFILES)