doc update

diff --git a/automake.texi b/automake.texi
index f0b91c6f4ed3623e9923bfefeb2947fe8d7d7a02..f1f1e81344d8f86b73d899cb7a96ab518d458320 100644 (file)
--- a/automake.texi
+++ b/automake.texi
@@ -567,11 +567,11 @@ bin_PROGRAMS = etags ctags
 ctags_SOURCES =
 ctags_LDADD = ctags.o
 
-etags.o:
-        $(COMPILE) -DETAGS_REGEXPS etags.c
+etags.o: etags.c
+        $(COMPILE) -DETAGS_REGEXPS -c etags.c
 
-ctags.o:
-        $(COMPILE) -DCTAGS -o ctags.o etags.c
+ctags.o: etags.c
+        $(COMPILE) -DCTAGS -o ctags.o -c etags.c
 @end example
 
 Note that @code{ctags_SOURCES} is defined to be empty---that way no
@@ -581,8 +581,28 @@ generate @code{etags} from @file{etags.o}.
 @code{ctags_LDADD} is used to get @file{ctags.o} into the link line.
 @code{ctags_DEPENDENCIES} is generated by Automake.
 
-Of course, these explicit rules do not work if the de-ANSI-fication
-feature is used; supporting that would require more work.
+The above rules won't work if your compiler doesn't accept both
+@samp{-c} and @samp{-o}.  The simplest fix for this is to introduce a
+bogus dependency (to avoid problems with a parallel @code{make}):
+
+@example
+etags.o: etags.c ctags.o
+        $(COMPILE) -DETAGS_REGEXPS -c etags.c
+
+ctags.o: etags.c
+        $(COMPILE) -DCTAGS -c etags.c && mv etags.o ctags.o
+@end example
+
+Also, these explicit rules do not work if the de-ANSI-fication feature
+is used; supporting that requires a little more work:
+
+@example
+etags._o: etags._c ctags.o
+        $(COMPILE) -DETAGS_REGEXPS -c etags.c
+
+ctags._o: etags._c
+        $(COMPILE) -DCTAGS -c etags.c && mv etags._o ctags.o
+@end example
 
 
 @node Invoking Automake