bug#6087: maint: extend the always_defined_macros syntax-check

[Jim Meyering]

Jim Meyering wrote:
> Three files in coreutils defined WIFSIGNALED and WTERMSIG macros
> to accommodate systems that lack them.  However, now that gnulib's
> sys/wait.h guarantees those, there's no point.  I've removed them.
>
>     maint: remove now-redundant definitions provided by sys/wait.h
>     * src/timeout.c (WIFSIGNALED, WTERMSIG): Remove definitions,
>     now that gnulib guarantees they are defined in <sys/wait.h>.
>     * src/operand2sig.c: Likewise.
>     * src/kill.c: Likewise.
>
> As usual, I want to ensure no regressions and remembered
> my always_defined_macros check (currently in coreutils' cfg.mk).
>
> I've extended that check to use not just its few listed .h files,
> but all 50+ that are now generated by gnulib.  The result uncovered
> some now-useless signal.h-provided macros, too.  I removed those in
> the next change set:
>
>     maint: remove now-redundant definitions provided by signal.h
>     * src/dd.c (SA_NODEFER, SA_RESETHAND): Remove definitions,
>     now that gnulib guarantees they are defined in <signal.h>.
>     * src/ls.c (SA_RESTART): Likewise.
>
> Finally, the 3rd change-set does this:
>
>     maint: extend the always_defined_macros syntax-check
>     * cfg.mk (gl_generated_headers_): Define.
>     (headers_with_interesting_macro_defs): Remove headers covered
>     by the above.
>     (.re-defmac): Extract symbol names from many more files.
>     (sc_always_defined_macros): Use VC_LIST_EXCEPT, not VC_LIST, so
>     that we can use the usual exception mechanism.
>     * .x-sc_always_defined_macros: New file.  Exempt src/seq.c.
>     * Makefile.am (syntax_check_exceptions): Add it here.
>
> I'll probably migrate this rule to gnulib after generalizing it some
> more (e.g., removing the system.h check).

I've pushed those changes to coreutils (slightly tweaked), along
with one more:

>From 7d501cdd9c1b7c37dd0c3c085c05969edd2917ee Mon Sep 17 00:00:00 2001
From: Jim Meyering <address@hidden>
Date: Mon, 3 May 2010 15:35:56 +0200
Subject: [PATCH] maint: factor trap-related code out of two syntax-check rules

* cfg.mk (gl_trap_): Define, using a loop and eval'd trap,
rather than repeated "trap" uses.  Also handle "13", SIGPIPE.
(sc_always_defined_macros): Use it.
(sc_system_h_headers): Likewise.
---
 cfg.mk |   15 +++++++++------
 1 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/cfg.mk b/cfg.mk
index 3bdf28c..679ea8e 100644
--- a/cfg.mk
+++ b/cfg.mk
@@ -135,13 +135,18 @@ gl_extract_significant_defines_ = \
          > address@hidden
        @mv address@hidden $@

+define gl_trap_
+  Exit () { set +e; (exit $$1); exit $$1; };                           \
+  for sig in 1 2 3 13 15; do                                           \
+    eval "trap 'Exit $$(expr $$sig + 128)' $$sig";                     \
+  done
+endef
+
 # Don't define macros that we already get from gnulib header files.
 sc_always_defined_macros: .re-defmac
        @if test -d $(gnulib_dir); then                                 \
          trap 'rc=$$?; rm -f .re-defmac; exit $$rc' 0;                 \
-         am__exit='(exit $rc); exit $rc';                              \
-         trap "rc=129; $$am__exit" 1; trap "rc=130; $$am__exit" 2;     \
-         trap "rc=131; $$am__exit" 3; trap "rc=143; $$am__exit" 15;    \
+         $(gl_trap_);                                                  \
          grep -f .re-defmac $$($(VC_LIST_EXCEPT))                      \
            && { echo '$(ME): define the above via some gnulib .h file' \
                  1>&2;  exit 1; } || :;                                \
@@ -161,9 +166,7 @@ sc_always_defined_macros: .re-defmac
 sc_system_h_headers: .re-list
        @if test -f $(srcdir)/src/system.h; then                        \
          trap 'rc=$$?; rm -f .re-list; exit $$rc' 0;                   \
-         am__exit='(exit $rc); exit $rc';                              \
-         trap "rc=129; $$am__exit" 1; trap "rc=130; $$am__exit" 2;     \
-         trap "rc=131; $$am__exit" 3; trap "rc=143; $$am__exit" 15;    \
+         $(gl_trap_);                                                  \
          grep -nE -f .re-list                                          \
              $$($(VC_LIST_EXCEPT) | grep '^src/')                      \
            && { echo '$(ME): the above are already included via system.h'\
--
1.7.1.335.g6845a