Backport upstream patch to fix C99 issue in configure script

Related to:

  <https://fedoraproject.org/wiki/Changes/PortingToModernC>
  <https://fedoraproject.org/wiki/Toolchain/PortingToModernC>

rrdtool-configure-c99.patch

@@ -0,0 +1,35 @@
+commit f3334fcbde0a77aa48938ba38602bff91c09cf85
+Author: Ryan Schmidt <git@ryandesign.com>
+Date:   Sun Mar 20 16:29:10 2022 -0500
+
+    acinclude.m4: Include <stdlib.h> when using exit
+    
+    Fixes:
+    
+    conftest.c:124:33: error: implicitly declaring library function 'exit'
+    with type 'void (int) __attribute__((noreturn))'
+
+diff --git a/m4/acinclude.m4 b/m4/acinclude.m4
+index d9d9eb25..0d6fbf5d 100644
+--- a/m4/acinclude.m4
++++ b/m4/acinclude.m4
+@@ -582,7 +582,8 @@ AC_DEFUN([GC_TIMEZONE], [
+         AC_REQUIRE([AC_STRUCT_TM])
+         AC_CACHE_CHECK([tm_gmtoff in struct tm], gq_cv_have_tm_gmtoff,
+                 gq_cv_have_tm_gmtoff=no
+-                AC_TRY_COMPILE([#include <time.h>
++                AC_TRY_COMPILE([#include <stdlib.h>
++                                #include <time.h>
+                                 #include <$ac_cv_struct_tm>
+                                 ],
+                                [struct tm t;
+@@ -595,7 +596,8 @@ AC_DEFUN([GC_TIMEZONE], [
+ 
+         AC_CACHE_CHECK([__tm_gmtoff in struct tm], gq_cv_have___tm_gmtoff,
+                 gq_cv_have___tm_gmtoff=no
+-                AC_TRY_COMPILE([#include <time.h>
++                AC_TRY_COMPILE([#include <stdlib.h>
++                                #include <time.h>
+                                 #include <$ac_cv_struct_tm>
+                                 ],
+                                [struct tm t;

rrdtool.spec

@@ -18,7 +18,7 @@
 Summary: Round Robin Database Tool to store and display time-series data
 Name: rrdtool
 Version: 1.8.0
-Release: 8%{?dist}
+Release: 9%{?dist}
 License: GPLv2+ with exceptions
 URL: https://oss.oetiker.ch/rrdtool/
 Source0: https://github.com/oetiker/rrdtool-1.x/releases/download/v%{version}/%{name}-%{version}.tar.gz
@@ -32,6 +32,7 @@ Patch4: rrdtool-1.4.8-php-ppc-fix.patch
 # Fix BUILD_DATE in rrdtool help output
 # https://github.com/oetiker/rrdtool-1.x/commit/e59f703
 Patch5: rrdtool-1.8.0-BUILD_DATE-fix.patch
+Patch6: rrdtool-configure-c99.patch
 
 BuildRequires: make
 BuildRequires: gcc-c++
@@ -180,6 +181,7 @@ The %{name}-lua package includes RRDtool bindings for Lua.
 %endif
 %patch4 -p1 -b .php-ppc-fix
 %patch5 -p1 -b .BUILD_DATE-fix
+%patch6 -p1 -b .configure-c99
 
 # Fix to find correct python dir on lib64
 perl -pi -e 's|get_python_lib\(0,0,prefix|get_python_lib\(1,0,prefix|g' \
@@ -408,6 +410,9 @@ LD_LIBRARY_PATH=%{buildroot}%{_libdir} php -n \
 %endif
 
 %changelog
+* Mon Apr 17 2023 Florian Weimer <fweimer@redhat.com> - 1.8.0-9
+- Backport upstream patch to fix C99 issue in configure script
+
 * Fri Jan 20 2023 Fedora Release Engineering <releng@fedoraproject.org> - 1.8.0-8
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild