Disable -Wdeprecated-non-prototype in the back branches.

There doesn't seem to be any good ABI-preserving way to silence
clang 15's -Wdeprecated-non-prototype warnings about our tree-walk
APIs.  While we've fixed it properly in HEAD, the only way to not
see hundreds of these in the back branches is to disable the
warnings.  We're not going to do anything about them, so we might
as well disable them.

I noticed that we also get some of these warnings about fmgr.c's
support for V0 function call convention, in branches before v10
where we removed that.  That's another area we aren't going to
change, so turning off the warning seems fine for that too.

Per project policy, this is a candidate for back-patching into
out-of-support branches: it suppresses annoying compiler warnings
but changes no behavior.  Hence, back-patch all the way to 9.2.

Discussion: https://postgr.es/m/CA+hUKGKpHPDTv67Y+s6yiC8KH5OXeDg6a-twWo_xznKTcG0kSA@mail.gmail.com

diff --git a/configure b/configure
index f5a3031979c58355e6458c1328d4b83aea040d74..50803aba6bfc52599807f7bc19ab9023084b0b0c 100755 (executable)
--- a/configure
+++ b/configure
@@ -4541,6 +4541,72 @@ fi
   if test -n "$NOT_THE_CFLAGS"; then
     CFLAGS="$CFLAGS -Wno-compound-token-split-by-macro"
   fi
+  # Similarly remove clang 15+'s deprecated-non-prototype, as it warns about
+  # tree-walking APIs that we can't reasonably change in the back branches.
+  NOT_THE_CFLAGS=""
+  { $as_echo "$as_me:$LINENO: checking whether $CC supports -Wdeprecated-non-prototype" >&5
+$as_echo_n "checking whether $CC supports -Wdeprecated-non-prototype... " >&6; }
+if test "${pgac_cv_prog_cc_cflags__Wdeprecated_non_prototype+set}" = set; then
+  $as_echo_n "(cached) " >&6
+else
+  pgac_save_CFLAGS=$CFLAGS
+CFLAGS="$pgac_save_CFLAGS -Wdeprecated-non-prototype"
+ac_save_c_werror_flag=$ac_c_werror_flag
+ac_c_werror_flag=yes
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+int
+main ()
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:$LINENO: $ac_try_echo\""
+$as_echo "$ac_try_echo") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  $as_echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+        test -z "$ac_c_werror_flag" ||
+        test ! -s conftest.err
+       } && test -s conftest.$ac_objext; then
+  pgac_cv_prog_cc_cflags__Wdeprecated_non_prototype=yes
+else
+  $as_echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+       pgac_cv_prog_cc_cflags__Wdeprecated_non_prototype=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+ac_c_werror_flag=$ac_save_c_werror_flag
+CFLAGS="$pgac_save_CFLAGS"
+fi
+{ $as_echo "$as_me:$LINENO: result: $pgac_cv_prog_cc_cflags__Wdeprecated_non_prototype" >&5
+$as_echo "$pgac_cv_prog_cc_cflags__Wdeprecated_non_prototype" >&6; }
+if test x"$pgac_cv_prog_cc_cflags__Wdeprecated_non_prototype" = x"yes"; then
+  NOT_THE_CFLAGS="${NOT_THE_CFLAGS} -Wdeprecated-non-prototype"
+fi
+
+  if test -n "$NOT_THE_CFLAGS"; then
+    CFLAGS="$CFLAGS -Wno-deprecated-non-prototype"
+  fi
   # Similarly disable useless truncation warnings from gcc 8+
   NOT_THE_CFLAGS=""
   { $as_echo "$as_me:$LINENO: checking whether $CC supports -Wformat-truncation" >&5

diff --git a/configure.in b/configure.in
index e98e8c005666017909b7e776586deae8ec3c2841..61fc5dcc1d83da59bec44324184df7af8b53fab4 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -442,6 +442,13 @@ if test "$GCC" = yes -a "$ICC" = no; then
   if test -n "$NOT_THE_CFLAGS"; then
     CFLAGS="$CFLAGS -Wno-compound-token-split-by-macro"
   fi
+  # Similarly remove clang 15+'s deprecated-non-prototype, as it warns about
+  # tree-walking APIs that we can't reasonably change in the back branches.
+  NOT_THE_CFLAGS=""
+  PGAC_PROG_CC_VAR_OPT(NOT_THE_CFLAGS, [-Wdeprecated-non-prototype])
+  if test -n "$NOT_THE_CFLAGS"; then
+    CFLAGS="$CFLAGS -Wno-deprecated-non-prototype"
+  fi
   # Similarly disable useless truncation warnings from gcc 8+
   NOT_THE_CFLAGS=""
   PGAC_PROG_CC_VAR_OPT(NOT_THE_CFLAGS, [-Wformat-truncation])