C compatibility fix for the configure script (#2252276)

Related to:

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

units-configure-c99.patch

@@ -0,0 +1,26 @@
+diff --git a/configure b/configure
+index 22c75a6222b06f68..43461d54e59f1568 100755
+--- a/configure
++++ b/configure
+@@ -3881,7 +3881,7 @@ else
+ int
+ main ()
+ {
+-wchar_t *out;char *in;char *res;
++wchar_t *out;char *in;const char *res;
+      res=setlocale(LC_CTYPE,"");res=in;
+      mbsrtowcs(out, &res, 2, NULL);
+      wcswidth(out,2);
+diff --git a/configure.ac b/configure.ac
+index c728d5c15d16ab2e..cd39f96e39f7d587 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -121,7 +121,7 @@ AC_CACHE_CHECK([for locale and UTF-8 support], am_cv_utf8,
+ #include <wchar.h>
+ #include <locale.h>
+ #include <langinfo.h>
+-], [wchar_t *out;char *in;char *res;
++], [wchar_t *out;char *in;const char *res;
+      res=setlocale(LC_CTYPE,"");res=in; 
+      mbsrtowcs(out, &res, 2, NULL);
+      wcswidth(out,2);],

units.spec

@@ -1,7 +1,7 @@
 Summary: A utility for converting amounts from one unit to another
 Name: units
 Version: 2.22
-Release: 6%{?dist}
+Release: 7%{?dist}
 Source: https://ftp.gnu.org/gnu/units/%{name}-%{version}.tar.gz
 URL: https://www.gnu.org/software/units/units.html
 License: GPL-3.0-or-later
@@ -14,6 +14,7 @@ BuildRequires: readline-devel
 
 # do not update currency.units from network during build
 Patch1: 0001-units-2.22-no-network.patch
+Patch2: units-configure-c99.patch
 
 %description
 Units converts an amount from one unit to another, or tells you what
@@ -52,6 +53,9 @@ make check
 %{_mandir}/man1/*
 
 %changelog
+* Thu Nov 30 2023 Florian Weimer <fweimer@redhat.com> - 2.22-7
+- C compatibility fix for the configure script (#2252276)
+
 * Sat Jul 22 2023 Fedora Release Engineering <releng@fedoraproject.org> - 2.22-6
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild