diff --git a/perl-configure-c99.patch b/perl-configure-c99.patch
new file mode 100644
index 0000000..91258f7
--- /dev/null
+++ b/perl-configure-c99.patch
@@ -0,0 +1,94 @@
+Avoid implicit ints and implicit function declarations, for improved
+compatibility with future compilers which will reject them by default.
+
+Submitted upstream: <https://github.com/Perl/perl5/pull/20718>
+
+diff --git a/Configure b/Configure
+index 9bd6a7ad9465c2ce..75c090edc37015da 100755
+--- a/Configure
++++ b/Configure
+@@ -4638,7 +4638,7 @@ esac
+ # so we will take those off from locincpth.
+ case "$gccversion" in
+ 3.*)
+-    echo "main(){}">try.c
++    echo "int main(){}">try.c
+     for incdir in $locincpth; do
+        warn=`$cc $ccflags -I$incdir -c try.c 2>&1 | \
+ 	     grep '^c[cp]p*[01]: warning: changing search order '`
+@@ -5771,6 +5771,7 @@ case "$intsize" in
+ #ifdef I_STDLIB
+ #include <stdlib.h>
+ #endif
++#include <stdio.h>
+ int main()
+ {
+ 	printf("intsize=%d;\n", (int)sizeof(int));
+@@ -6844,6 +6845,7 @@ case "$doublesize" in
+ #ifdef I_STDLIB
+ #include <stdlib.h>
+ #endif
++#include <stdio.h>
+ int main()
+ {
+     printf("%d\n", (int)sizeof(double));
+@@ -12606,7 +12608,7 @@ case "$dlsrc" in
+ dl_dlopen.xs)
+ 	echo "Checking whether your dlsym() needs a leading underscore ..." >&4
+ 	$cat >dyna.c <<'EOM'
+-fred () { }
++void fred (void) { }
+ EOM
+ 
+ $cat >fred.c<<EOM
+@@ -12625,7 +12627,7 @@ $cat >fred.c<<EOM
+ #include <link.h>
+ #endif
+ 
+-extern int fred() ;
++extern void fred(void) ;
+ 
+ int main()
+ {
+@@ -13659,6 +13661,7 @@ $cat >try.c <<EOP
+ #ifdef I_STDLIB
+ #include <stdlib.h>
+ #endif
++#include <string.h>
+ #define FILE_ptr(fp)	$stdio_ptr
+ #define FILE_cnt(fp)	$stdio_cnt
+ int main() {
+@@ -16166,6 +16169,7 @@ echo "Checking to see if your libm supports _LIB_VERSION..." >&4
+ $cat >try.c <<EOCP
+ #include <unistd.h>
+ #include <math.h>
++#include <stdio.h>
+ int main (int argc, char *argv[])
+ {
+     printf ("%d\n", _LIB_VERSION);
+@@ -22063,13 +22067,15 @@ pager="$ans"
+ : see if ar generates random libraries by itself
+ echo " "
+ echo "Checking how to generate random libraries on your machine..." >&4
+-echo 'int bar1() { return bar2(); }' > bar1.c
++echo 'extern int bar2(); int bar1() { return bar2(); }' > bar1.c
+ echo 'int bar2() { return 2; }' > bar2.c
+ $cat > foo.c <<EOP
+ #$i_stdlib I_STDLIB
+ #ifdef I_STDLIB
+ #include <stdlib.h>
+ #endif
++#include <stdio.h>
++extern int bar1();
+ int main() { printf("%d\n", bar1()); exit(0); }
+ EOP
+ $cc $ccflags -c bar1.c >/dev/null 2>&1
+@@ -22295,7 +22301,7 @@ EOM
+ 			for nfd in 'int' 'size_t' 'unsigned long' 'unsigned' ; do
+ 				for tmo in 'struct timeval *' 'const struct timeval *'; do
+ 					case "$val" in
+-					'')	try="$extern_C select _(($nfd, $xxx, $xxx, $xxx, $tmo));"
++					'')	try="$extern_C int select _(($nfd, $xxx, $xxx, $xxx, $tmo));"
+ 						if ./protochk "$try" $hdrs; then
+ 							echo "Your system accepts $xxx."
+ 							val="$xxx"
diff --git a/perl.spec b/perl.spec
index c9e0175..7f82cd4 100644
--- a/perl.spec
+++ b/perl.spec
@@ -104,7 +104,7 @@ License:        GPL+ or Artistic
 Epoch:          %{perl_epoch}
 Version:        %{perl_version}
 # release number must be even higher, because dual-lived modules will be broken otherwise
-Release:        493%{?dist}
+Release:        494%{?dist}
 Summary:        Practical Extraction and Report Language
 Url:            https://www.perl.org/
 Source0:        https://www.cpan.org/src/5.0/perl-%{perl_version}.tar.xz
@@ -176,6 +176,7 @@ Patch201:       perl-5.16.3-Link-XS-modules-to-libperl.so-with-EU-MM-on-Linux.pa
 
 # If optimizing -O is used, add the definition to .ph files, bug #2152012
 Patch202:       perl-5.36.0-Add-definition-of-OPTIMIZE-to-.ph-files.patch
+Patch203: perl-configure-c99.patch
 
 # Update some of the bundled modules
 # see http://fedoraproject.org/wiki/Perl/perl.spec for instructions
@@ -4199,6 +4200,7 @@ you're not running VMS, this module does nothing.
 %patch200 -p1
 %patch201 -p1
 %patch202 -p1
+%patch203 -p1
 
 %if !%{defined perl_bootstrap}
 # Local patch tracking
@@ -7003,6 +7005,9 @@ popd
 
 # Old changelog entries are preserved in CVS.
 %changelog
+* Tue Jan 17 2023 Florian Weimer <fweimer@redhat.com> - 4:5.36.0-494
+- Port Configure script to C99
+
 * Tue Jan 10 2023 Jitka Plesnikova <jplesnik@redhat.com> - 4:5.36.0-493
 - Add definition of OPTIMIZE to .ph files, if optimizing is used