Hi John, > In the Octave sources, we limit the direct use of gnulib header files to > one convenience library so we add > > -Ilibgnu -I$(srcdir)/libgnu > > to one library-specific CPPFLAGS variable, > %canon_reldir%_libwrappers_la_CPPFLAGS. We don't want to add them to > AM_CPPFLAGS and have them used in every rule for compiling source files, > so instead of doing that, I used > > libgnu_libgnu_la_CPPFLAGS = -Ilibgnu -I$(srcdir)/libgnu > > This setting almost works but I ran into failures when compiling some > object files (gnulib headers not found). For example, compiling > mktime.c failed. The generated Makefile includes the following rule > that uses $(libgnu_libgnu_la_CPPFLAGS): > > libgnu/libgnu_la-mktime.lo: libgnu/mktime.c > $(AM_V_CC)$(LIBTOOL) $(AM_V_lt) --tag=CC $(AM_LIBTOOLFLAGS) > $(LIBTOOLFLAGS) --mode=compile $(CC) $(DEFS) $(DEFAULT_INCLUDES) > $(INCLUDES) $(libgnu_libgnu_la_CPPFLAGS) $(CPPFLAGS) > $(libgnu_libgnu_la_CFLAGS) $(CFLAGS) -MT libgnu/libgnu_la-mktime.lo -MD > -MP -MF libgnu/$(DEPDIR)/libgnu_la-mktime.Tpo -c -o > libgnu/libgnu_la-mktime.lo `test -f 'libgnu/mktime.c' || echo > '$(srcdir)/'`libgnu/mktime.c > $(AM_V_at)$(am__mv) libgnu/$(DEPDIR)/libgnu_la-mktime.Tpo > libgnu/$(DEPDIR)/libgnu_la-mktime.Plo > > However, this rule is not used because libgnu/libgnu_la-mktime.lo does > not appear as a dependency of libgnu/libgnu.la. Instead, > libgnu/mktime.lo appears in the gl_LTLIBOBJS list that is ultimately a > dependency of libgnu/libgnu.la. Because of that, it seems that the > .c.lo suffix rule is used instead:
It seems like the problem you are hitting is the same that was partially solved in <https://lists.gnu.org/archive/html/bug-gnulib/2022-01/msg00078.html>. Unfortunately, as written there, it's solved only to 90%. The 'mktime' module, for example, still contains an AC_LIBOBJ invocation, which leads to an entry in $(gl_LTLIBOBJS). The last 10% will/would be more work than the first 90%. > BTW, it appears that the same thing happens when using a recursive > Makefile for gnulib but I didn't notice it because when the compile > rules are executed in the sub-make, the definition of > $(DEFAULT_INCLUDES) does the right thing and is limited to the libgnu > directory because of using a recursive Makefile. So, it appears that your two goals — a non-recursive Makefile structure and good isolation of the different directories from each other — are contradictory. You can get one of them, but not both. Bruno
