[FYI] {master} compat: reinstate support for obsolete $(INCLUDES) variable

[Stefano Lattarini]

Since INCLUDES and AM_CPPFLAGS can be both used at the same time in a
single project, and interact in a non-obvious way, switching away from
INCLUDES is, unfortunately, not simply a matter of doing a mindless
INCLUDES -> AM_CPPFLAGS substitution.  In fact, the transition from a
"INCLUDES + CPPFLAGS" setup to a "AM_CPPFLAGS only" setup could cause
subtle bugs to sneak into the build systems of the client packages
doing the transition.  Forcing this risk upon our users is definitely
not worth the small enhancement in consistency and cleanliness that
the removal of INCLUDES would give us.

For a more extended rationale and related discussions, see:
<http://lists.gnu.org/archive/html/automake/2013-02/msg00001.html>

This change basically reverts commit v1.13-8-g880595d.

* automake.in: Re-introduce support for INCLUDES (its use will cause
warnings in the 'obsolete' category rather than fatal errors).
* doc/automake.texi: Adjust to re-add mention of INCLUDES.
* t/includes-no-more.sh: Rename ...
* t/includes-deprecation.sh: ... like this, and adjust.
* t/list-of-tests.mk: Update.
* t/warnopts.sh: Minor fixlet while at it.

Suggested-by: Peter Rosin <address@hidden>
Signed-off-by: Stefano Lattarini <address@hidden>
---
 NEWS                                               |  3 ---
 automake.in                                        | 25 +++++++++++++---------
 doc/automake.texi                                  | 14 ++++++++----
 t/{includes-no-more.sh => includes-deprecation.sh} | 17 +++++++++++----
 t/list-of-tests.mk                                 |  2 +-
 t/warnopts.sh                                      |  8 ++-----
 6 files changed, 41 insertions(+), 28 deletions(-)
 rename t/{includes-no-more.sh => includes-deprecation.sh} (67%)

diff --git a/NEWS b/NEWS
index 6f16380..fb70eee 100644
--- a/NEWS
+++ b/NEWS
@@ -30,9 +30,6 @@ New in 2.0:
     been removed.  It should be safe to simply remove any definition
     of it you have in your Makefiles.
 
-  - Support for the long-obsolete $(INCLUDES) variable has been finally
-    removed, in favour of the modern equivalent $(AM_CPPFLAGS).
-
 * Removed support for obsolete platforms:
 
   - Support for automatic dependency tracking with the SGI C/C++ compilers
diff --git a/automake.in b/automake.in
index 4275b57..0dcf06b 100644
--- a/automake.in
+++ b/automake.in
@@ -604,6 +604,7 @@ my @cpplike_flags =
   qw{
     $(DEFS)
     $(DEFAULT_INCLUDES)
+    $(INCLUDES)
     $(AM_CPPFLAGS)
     $(CPPFLAGS)
   };
@@ -790,9 +791,9 @@ register_language ('name' => 'asm',
                   'config_vars' => ['CCAS', 'CCASFLAGS'],
 
                   'flags' => ['CCASFLAGS'],
-                  # Users can set AM_CCASFLAGS to include $(DEFS) or
-                  # or anything else required.  They can also set CCAS.
-                  # Or simply use Preprocessed Assembler.
+                  # Users can set AM_CCASFLAGS to include $(DEFS),
+                   # $(INCLUDES), or anything else required.  They can also
+                   # set CCAS.  Or simply use Preprocessed Assembler.
                   'compile' => '$(CCAS) $(AM_CCASFLAGS) $(CCASFLAGS)',
                   'ccer' => 'CCAS',
                   'compiler' => 'CCASCOMPILE',
@@ -871,9 +872,9 @@ register_language ('name' => 'ppfc',
 # Preprocessed Fortran 77
 #
 # The current support for preprocessing Fortran 77 just involves
-# passing "$(DEFS) $(DEFAULT_INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS)"
-# as additional flags to the Fortran 77 compiler, since this is
-# how GNU Make does it; see the "GNU Make Manual, Edition 0.51
+# passing "$(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS)
+# $(CPPFLAGS)" as additional flags to the Fortran 77 compiler, since
+# this is how GNU Make does it; see the "GNU Make Manual, Edition 0.51
 # for 'make' Version 3.76 Beta" (specifically, from info file
 # '(make)Catalogue of Rules').
 #
@@ -7724,14 +7725,18 @@ sub generate_makefile
     }
 
   # Catch some obsolete variables.
-  reject_var 'INCLUDES', "'INCLUDES' is the obsolete name for " .
-                         "'AM_CPPFLAGS' (or '*_CPPFLAGS')";
-  if (my $amflags = var ('ACLOCAL_AMFLAGS'))
+  if (my $ovar = var ('ACLOCAL_AMFLAGS'))
     {
-      msg_var 'obsolete', $amflags,
+      msg_var 'obsolete', $ovar,
               "'ACLOCAL_AMFLAGS' is deprecated; use 'AC_CONFIG_MACRO_DIRS'"
               . " in configure.ac instead";
     }
+  if (my $ovar = var ('INCLUDES'))
+    {
+      msg_var 'obsolete', $ovar,
+              "'INCLUDES' is deprecated; you should use 'AM_CPPFLAGS'"
+              . " (or '*_CPPFLAGS') instead"
+    }
 
   # Must do this after reading .am file.
   define_variable ('subdir', $relative_dir, INTERNAL);
diff --git a/doc/automake.texi b/doc/automake.texi
index deb96d3..ec17160 100644
--- a/doc/automake.texi
+++ b/doc/automake.texi
@@ -6117,6 +6117,12 @@ files in the source directory are ignored.
 @code{AM_CPPFLAGS} is ignored in preference to a per-executable (or
 per-library) @code{_CPPFLAGS} variable if it is defined.
 
address@hidden INCLUDES
+This does the same job as @code{AM_CPPFLAGS} (or any per-target
address@hidden variable if it is used).  It is an older name for the
+same functionality.  This variable is deprecated; we suggest using
address@hidden and per-target @code{_CPPFLAGS} instead.
+
 @item AM_CFLAGS
 This is the variable the @file{Makefile.am} author can use to pass
 in additional C compiler flags.  In some situations, this is
@@ -6449,8 +6455,8 @@ assembly code.  This compiler must work a bit like a C 
compiler; in
 particular it must accept @option{-c} and @option{-o}.  The values of
 @code{CCASFLAGS} and @code{AM_CCASFLAGS} (or its per-target
 definition) is passed to the compilation.  For preprocessed files,
address@hidden, @code{DEFAULT_INCLUDES}, @code{CPPFLAGS} and
address@hidden are also used.
address@hidden, @code{DEFAULT_INCLUDES}, @code{INCLUDES}, @code{CPPFLAGS}
+and @code{AM_CPPFLAGS} are also used.
 
 The autoconf macro @code{AM_PROG_AS} will define @code{CCAS} and
 @code{CCASFLAGS} for you (unless they are already set, it simply sets
@@ -6539,7 +6545,7 @@ command used is as follows:
 @table @file
 
 @item .F
address@hidden(F77) -F $(DEFS) $(AM_CPPFLAGS) $(CPPFLAGS)@*
address@hidden(F77) -F $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS)@*
 $(AM_FFLAGS) $(FFLAGS)}
 
 @item .r
@@ -6562,7 +6568,7 @@ is as follows:
 @code{$(F77) -c $(AM_FFLAGS) $(FFLAGS)}
 
 @item .F
address@hidden(F77) -c $(DEFS) $(AM_CPPFLAGS) $(CPPFLAGS)@*
address@hidden(F77) -c $(DEFS) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS)@*
 $(AM_FFLAGS) $(FFLAGS)}
 
 @item .r
diff --git a/t/includes-no-more.sh b/t/includes-deprecation.sh
similarity index 67%
rename from t/includes-no-more.sh
rename to t/includes-deprecation.sh
index 4867ee5..ec54359 100755
--- a/t/includes-no-more.sh
+++ b/t/includes-deprecation.sh
@@ -14,19 +14,28 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-# Support for $(INCLUDES) has been removed.
+# Support for $(INCLUDES) is deprecated.
 
 . test-init.sh
 
 echo AC_PROG_CC >> configure.ac
 
+$ACLOCAL
+
 cat > Makefile.am << 'END'
 bin_PROGRAMS = foo
 INCLUDES = -DFOO
 END
 
-$ACLOCAL
-AUTOMAKE_fails -Wnone -Wno-error
-grep "^Makefile\\.am:2:.* 'INCLUDES'.* obsolete.* 'AM_CPPFLAGS'" stderr
+AUTOMAKE_fails -Wnone -Wobsolete
+grep "^Makefile\\.am:2:.* 'INCLUDES'.* deprecated.* 'AM_CPPFLAGS'" stderr
+AUTOMAKE_run -Wall -Wno-obsolete
+test ! -s stderr
+
+echo 'AC_SUBST([INCLUDES])' >> configure.ac
+sed '/^INCLUDES/d' Makefile.am > t && mv -f t Makefile.am
+
+AUTOMAKE_run -Wno-error
+grep "^configure\\.ac:5:.* 'INCLUDES'.* deprecated.* 'AM_CPPFLAGS'" stderr
 
 :
diff --git a/t/list-of-tests.mk b/t/list-of-tests.mk
index c0fe1bd..1c069ef 100644
--- a/t/list-of-tests.mk
+++ b/t/list-of-tests.mk
@@ -500,7 +500,7 @@ t/help-silent.sh \
 t/help-upc.sh \
 t/hfs.sh \
 t/implicit.sh \
-t/includes-no-more.sh \
+t/includes-deprecation.sh \
 t/init.sh \
 t/init2.sh \
 t/insh2.sh \
diff --git a/t/warnopts.sh b/t/warnopts.sh
index 7e1a2d5..f1c4c8c 100755
--- a/t/warnopts.sh
+++ b/t/warnopts.sh
@@ -63,12 +63,8 @@ test $(grep -v 'warnings are treated as errors' stderr | wc 
-l) = 3
 rm -rf autom4te*.cache
 
 # If we add a global -Wnone, all warnings should disappear.
-cat >configure.ac <<END
-AC_INIT([warnopts], [1.0])
-AM_INIT_AUTOMAKE([-Wnone])
-AC_CONFIG_FILES([Makefile sub/Makefile])
-AC_OUTPUT
-END
+sed 's/^AM_INIT_AUTOMAKE/AM_INIT_AUTOMAKE([-Wnone])/' configure.ac > t
+mv -f t configure.ac
 $ACLOCAL
 $AUTOMAKE
 
-- 
1.8.2.1.389.gcaa7d79