diff --git a/dfu-programmer-c99.patch b/dfu-programmer-c99.patch
new file mode 100644
index 0000000..ad03798
--- /dev/null
+++ b/dfu-programmer-c99.patch
@@ -0,0 +1,16 @@
+Include <stdlib.h> for the malloc function.
+
+Submitted upstream: <https://github.com/dfu-programmer/dfu-programmer/pull/76>
+
+diff --git a/src/atmel.c b/src/atmel.c
+index 4ea794d17f65d8d0..491bbb16706e65a8 100644
+--- a/src/atmel.c
++++ b/src/atmel.c
+@@ -19,6 +19,7 @@
+  */
+ 
+ #include <stdio.h>
++#include <stdlib.h>
+ #include <stdarg.h>
+ #include <stdint.h>
+ #include <string.h>
diff --git a/dfu-programmer-configure-c99.patch b/dfu-programmer-configure-c99.patch
new file mode 100644
index 0000000..cff5b17
--- /dev/null
+++ b/dfu-programmer-configure-c99.patch
@@ -0,0 +1,28 @@
+This is merely a kludge to fix a configure.ac bug:
+
+  Missing #include <string.h> in AC_FUNC_MEMCMP
+  <https://savannah.gnu.org/support/index.php?110530>
+
+  Misuse of autoconf features in configure.ac causes multiple problems
+  <https://github.com/dfu-programmer/dfu-programmer/issues/61>
+
+We cannot re-run autoconf with the current Fedora autoconf version,
+and this patch serves as a reminder that something has to be done
+to fix configure.ac to address this AC_FUNC_MEMCMP issue.  The
+next upstream release has fixed this by removing old libusb support:
+
+  Remove libusb0 support
+  <https://github.com/dfu-programmer/dfu-programmer/pull/66>
+
+diff --git a/configure b/configure
+index 77c9bef30edcbd2e..d4fcdf174a7fcd14 100755
+--- a/configure
++++ b/configure
+@@ -4596,6 +4596,7 @@ else
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+ /* end confdefs.h.  */
+ $ac_includes_default
++#include <string.h>
+ int
+ main ()
+ {
diff --git a/dfu-programmer.spec b/dfu-programmer.spec
index 83062db..7089578 100644
--- a/dfu-programmer.spec
+++ b/dfu-programmer.spec
@@ -1,11 +1,13 @@
 Name:           dfu-programmer
 Version:        0.7.2
-Release:        11%{?dist}
+Release:        12%{?dist}
 Summary:        A Device Firmware Update based USB programmer for Atmel chips
 
 License:        GPLv2+
 URL:            http://dfu-programmer.github.io/
 Source0:        https://downloads.sourceforge.net/%{name}/%{name}-%{version}.tar.gz
+Patch0:         dfu-programmer-configure-c99.patch
+Patch1:         dfu-programmer-c99.patch
 
 BuildRequires:  gcc
 BuildRequires:  pkgconfig(libusb-1.0) >= 1.0.0
@@ -18,7 +20,7 @@ bootloader supporting ISP. This is a mostly Device Firmware Update
 Atmel chips with USB support.
 
 %prep
-%setup -q
+%autosetup -p1
 
 %build
 %configure
@@ -34,6 +36,9 @@ Atmel chips with USB support.
 %{_mandir}/man1/%{name}.1*
 
 %changelog
+* Mon Dec 12 2022 Florian Weimer <fweimer@redhat.com> - 0.7.2-12
+- Port to C99 (#2152666)
+
 * Thu Jul 21 2022 Fedora Release Engineering <releng@fedoraproject.org> - 0.7.2-11
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_37_Mass_Rebuild