From fed9cf2cb9ef4cdc3fe8b09dc2eb19e82fe1cc8b Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 12 Dec 2021 14:54:37 -0500
Subject: [PATCH] Use return instead of exit() in configure

Using exit() requires stdlib.h, which is not included.  Use return
instead.  Also add return type for main().

This back-patches commit 1c0cf52b3 into out-of-support branches,
pursuant to a newly-established project policy that we'll try to keep
out-of-support branches buildable on modern platforms for at least
ten major releases back, ensuring people can test pg_dump and psql
compatibility against servers that far back.  With the current
development branch being v15, that works out to keeping 9.2 and up
buildable as of today.

This fix is needed to get through 'configure' when using recent
macOS (and possibly other clang-based toolchains).  It seems to
be sufficient to get through 'check-world', although there are
annoyances such as compiler warnings, which will be dealt with
separately.

Original patch by Peter Eisentraut

Discussion: https://postgr.es/m/d0316012-ece7-7b7e-2d36-9c38cb77cb3b@enterprisedb.com
---
 config/c-compiler.m4 |  4 +++-
 config/c-library.m4  |  4 +++-
 configure            | 12 +++++++++---
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/config/c-compiler.m4 b/config/c-compiler.m4
index 8a216c9f73c..349e0932a9f 100644
--- a/config/c-compiler.m4
+++ b/config/c-compiler.m4
@@ -84,8 +84,10 @@ int does_int64_work()
     return 0;
   return 1;
 }
+
+int
 main() {
-  exit(! does_int64_work());
+  return (! does_int64_work());
 }],
 [Ac_cachevar=yes],
 [Ac_cachevar=no],
diff --git a/config/c-library.m4 b/config/c-library.m4
index 70eb0e4dcf7..d1849214645 100644
--- a/config/c-library.m4
+++ b/config/c-library.m4
@@ -250,8 +250,10 @@ int does_int64_snprintf_work()
     return 0;			/* either multiply or snprintf is busted */
   return 1;
 }
+
+int
 main() {
-  exit(! does_int64_snprintf_work());
+  return (! does_int64_snprintf_work());
 }],
 [pgac_cv_snprintf_long_long_int_format=$pgac_format; break],
 [],
diff --git a/configure b/configure
index 6c2a1755ce7..23486236442 100755
--- a/configure
+++ b/configure
@@ -24588,8 +24588,10 @@ int does_int64_work()
     return 0;
   return 1;
 }
+
+int
 main() {
-  exit(! does_int64_work());
+  return (! does_int64_work());
 }
 _ACEOF
 rm -f conftest$ac_exeext
@@ -24725,8 +24727,10 @@ int does_int64_work()
     return 0;
   return 1;
 }
+
+int
 main() {
-  exit(! does_int64_work());
+  return (! does_int64_work());
 }
 _ACEOF
 rm -f conftest$ac_exeext
@@ -24829,8 +24833,10 @@ int does_int64_snprintf_work()
     return 0;			/* either multiply or snprintf is busted */
   return 1;
 }
+
+int
 main() {
-  exit(! does_int64_snprintf_work());
+  return (! does_int64_snprintf_work());
 }
 _ACEOF
 rm -f conftest$ac_exeext