diff --git a/aalib-c99.patch b/aalib-c99.patch
new file mode 100644
index 0000000000000000000000000000000000000000..2a65cc2382955e697eed915664d72220995ea45c
--- /dev/null
+++ b/aalib-c99.patch
@@ -0,0 +1,108 @@
+Add additional system header #include directives for more
+function prototypes.  This avoids implicit function declarations
+and build failures with future compilers.
+
+Submitted upstream: <https://sourceforge.net/p/aa-project/bugs/10/>
+
+diff --git a/src/aafire.c b/src/aafire.c
+index 4f36149aa84fba57..a59b5c5fa58e085b 100644
+--- a/src/aafire.c
++++ b/src/aafire.c
+@@ -1,4 +1,5 @@
+ #include <stdio.h>
++#include <stdlib.h>
+ #include "aalib.h"
+ 
+ #define XSIZ aa_imgwidth(context)
+diff --git a/src/aainfo.c b/src/aainfo.c
+index d3f6d50f34590638..f4250ee37ae46134 100644
+--- a/src/aainfo.c
++++ b/src/aainfo.c
+@@ -1,3 +1,4 @@
++#include <stdlib.h>
+ 
+ #include "aalib.h"
+ #include "aaint.h"
+diff --git a/src/aakbdreg.c b/src/aakbdreg.c
+index def65fe25646d75a..682616313c1b6ebd 100644
+--- a/src/aakbdreg.c
++++ b/src/aakbdreg.c
+@@ -1,4 +1,5 @@
+ #include <malloc.h>
++#include <string.h>
+ #include "config.h"
+ #include "aalib.h"
+ #include "aaint.h"
+diff --git a/src/aalib.c b/src/aalib.c
+index 11fecc8fe8ef6b59..1ef12c0dfa9026a4 100644
+--- a/src/aalib.c
++++ b/src/aalib.c
+@@ -1,4 +1,5 @@
+ #include <stdio.h>
++#include <stdlib.h>
+ #include <string.h>
+ #include <malloc.h>
+ #include "aalib.h"
+diff --git a/src/aalinuxkbd.c b/src/aalinuxkbd.c
+index c7f388abfe9e8c7f..ea988154518dfc8e 100644
+--- a/src/aalinuxkbd.c
++++ b/src/aalinuxkbd.c
+@@ -8,6 +8,7 @@
+  */
+ 
+ #include "config.h"
++#include <stdlib.h>
+ #ifdef LINUX_DRIVER
+ #include <sys/time.h>
+ #include <sys/types.h>
+diff --git a/src/aamoureg.c b/src/aamoureg.c
+index 03808289eb59b928..6d807416ae0d3dc2 100644
+--- a/src/aamoureg.c
++++ b/src/aamoureg.c
+@@ -1,4 +1,5 @@
+ #include <malloc.h>
++#include <string.h>
+ #include "config.h"
+ #include "aalib.h"
+ #include "aaint.h"
+diff --git a/src/aaregist.c b/src/aaregist.c
+index 54abec0b9797533a..768b8ce29e286b00 100644
+--- a/src/aaregist.c
++++ b/src/aaregist.c
+@@ -1,4 +1,5 @@
+ #include <malloc.h>
++#include <string.h>
+ #include "config.h"
+ #include "aalib.h"
+ #include "aaint.h"
+diff --git a/src/aasavefont.c b/src/aasavefont.c
+index b00e1e6d7f181952..864ba225d5ef626c 100644
+--- a/src/aasavefont.c
++++ b/src/aasavefont.c
+@@ -1,3 +1,4 @@
++#include <stdlib.h>
+ #include "aalib.h"
+ int main(int argc, char **argv)
+ {
+diff --git a/src/aatest.c b/src/aatest.c
+index 9816f5d855134894..89933cfba6344270 100644
+--- a/src/aatest.c
++++ b/src/aatest.c
+@@ -1,3 +1,5 @@
++#include <stdlib.h>
++#include <string.h>
+ #include "aalib.h"
+ int main(int argc, char **argv)
+ {
+diff --git a/src/aaxkbd.c b/src/aaxkbd.c
+index f16afc63bb565512..44b91458b4bef3bc 100644
+--- a/src/aaxkbd.c
++++ b/src/aaxkbd.c
+@@ -7,6 +7,7 @@
+ #include <X11/Xlib.h>
+ #include <X11/keysymdef.h>
+ #include <X11/keysym.h>
++#include <X11/Xutil.h>
+ #include "aalib.h"
+ #include "aaint.h"
+ #include "aaxint.h"
diff --git a/aalib.spec b/aalib.spec
index 93f8fff9596cc7755d0df6cef284899019adcc95..398fe2903487845af680478bb31e2814acf6733c 100644
--- a/aalib.spec
+++ b/aalib.spec
@@ -1,6 +1,6 @@
 Name:           aalib
 Version:        1.4.0
-Release:        3
+Release:        4
 Summary:        An ASCII Art Library
 License:        GPL-2.0+
 URL:            http://aa-project.sourceforge.net/aalib/
@@ -8,6 +8,7 @@ Source0:        http://download.sourceforge.net/aa-project/aalib-1.4rc5.tar.gz
 # Fix missing return value
 Patch0001:      aalib-1.4rc5-bug149361.patch
 Patch0002:      aalib-1.4rc5-opaque-ncurses-fix.patch
+Patch0003:      aalib-c99.patch
 BuildRequires:  slang-devel libXt-devel gpm-devel ncurses-devel autoconf libtool
 Provides:       %{name}-libs = %{version}-%{release}
 Obsoletes:      %{name}-libs < %{version}-%{release}
@@ -79,6 +80,9 @@ fi
 %{_mandir}/man3/*
 
 %changelog
+* Mon Jul 28 2025 Liu Qingtao <liu.qingtao2@zte.com.cn> -1.4.0-4
+- backport from fedoraproject to port to C99
+
 * Fri Dec 20 2024 yaoxin <yao_xin001@hoperun.com> - 1.4.0-3
 - Fix build failure caused by ncurses update to 6.5