diff --git a/createrepo_c-c99.patch b/createrepo_c-c99.patch
new file mode 100644
index 0000000..63d8ab0
--- /dev/null
+++ b/createrepo_c-c99.patch
@@ -0,0 +1,16 @@
+Include <rpm/rpmstring.h> for the rasprintf function prototype, to
+avoid an implicit function declaration.  Improves compatibility with
+future compilers.
+
+diff --git a/src/xml_file.c b/src/xml_file.c
+index e369f5170f181758..d74af230081fb3d0 100644
+--- a/src/xml_file.c
++++ b/src/xml_file.c
+@@ -20,6 +20,7 @@
+ #include <glib.h>
+ #include <glib/gstdio.h>
+ #include <assert.h>
++#include <rpm/rpmstring.h>
+ #include "xml_file.h"
+ #include <errno.h>
+ #include "error.h"
diff --git a/createrepo_c.spec b/createrepo_c.spec
index 33d8b98..d8d3a15 100644
--- a/createrepo_c.spec
+++ b/createrepo_c.spec
@@ -31,10 +31,11 @@
 Summary:        Creates a common metadata repository
 Name:           createrepo_c
 Version:        0.20.1
-Release:        2%{?dist}
+Release:        3%{?dist}
 License:        GPLv2+
 URL:            https://github.com/rpm-software-management/createrepo_c
 Source0:        %{url}/archive/%{version}/%{name}-%{version}.tar.gz
+Patch0: createrepo_c-c99.patch
 
 BuildRequires:  cmake
 BuildRequires:  gcc
@@ -182,6 +183,9 @@ ln -sr %{buildroot}%{_bindir}/modifyrepo_c %{buildroot}%{_bindir}/modifyrepo
 %{python3_sitearch}/%{name}-%{version}-py%{python3_version}.egg-info
 
 %changelog
+* Sat Feb 25 2023 Florian Weimer <fweimer@redhat.com> - 0.20.1-3
+- Apply upstream patch to fix C99 compatibility issue
+
 * Thu Jan 19 2023 Fedora Release Engineering <releng@fedoraproject.org> - 0.20.1-2
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_38_Mass_Rebuild