diff --git a/tinyfigue-configure-c99.patch b/tinyfigue-configure-c99.patch
new file mode 100644
index 0000000..42810a8
--- /dev/null
+++ b/tinyfigue-configure-c99.patch
@@ -0,0 +1,21 @@
+Fix old autoconf-generated code for compatibility with C99: undeclared
+functions can now longer be called.
+
+Fixed in <https://github.com/ingwarsw/tinyfugue> by moving to current
+autoconf.
+
+diff --git a/configure b/configure
+index ea48217c90151d8f..9d4a80250acf575a 100755
+--- a/configure
++++ b/configure
+@@ -3060,8 +3060,8 @@ main ()
+   for (i = 0; i < 256; i++)
+     if (XOR (islower (i), ISLOWER (i))
+ 	|| toupper (i) != TOUPPER (i))
+-      exit(2);
+-  exit (0);
++      return 2;
++  return 0;
+ }
+ _ACEOF
+ rm -f conftest$ac_exeext
diff --git a/tinyfugue-malloc-c99.h b/tinyfugue-malloc-c99.h
new file mode 100644
index 0000000..3a0037e
--- /dev/null
+++ b/tinyfugue-malloc-c99.h
@@ -0,0 +1,18 @@
+Include <stdlib.h> for !USE_MMALLOC, so that the malloc etc.
+prototypes are available.  For C99 compatibility.
+
+This seems to have been fixed in <https://github.com/ingwarsw/tinyfugue>
+in a different way.
+
+diff --git a/src/malloc.h b/src/malloc.h
+index cc4d3bf317b09b06..2e649de2651c1edf 100644
+--- a/src/malloc.h
++++ b/src/malloc.h
+@@ -34,6 +34,7 @@ extern int low_memory_warning;
+ # define realloc(ptr, size)		mrealloc(NULL, ptr, size)
+ # define free(ptr)			mfree(NULL, ptr)
+ #else
++# include <stdlib.h>
+ # define mmalloc(md, size)		malloc(size)
+ # define mcalloc(md, size)		calloc(size)
+ # define mrealloc(md, ptr, size)	realloc(ptr, size)
diff --git a/tinyfugue-tfio-c99.patch b/tinyfugue-tfio-c99.patch
new file mode 100644
index 0000000..f7b474e
--- /dev/null
+++ b/tinyfugue-tfio-c99.patch
@@ -0,0 +1,26 @@
+Include "socket.h" for main_loop prototype. For C99 compatibility.
+
+Also fixed via this in <https://github.com/ingwarsw/tinyfugue>:
+
+commit 7b280f0f54dac62342c4f2a13a70b79bfb01a7b8
+Author: Karol Lassak <ingwar@ingwar.eu.org>
+Date:   Wed Dec 2 15:04:42 2020 +0000
+
+    Add actions file (#31)
+    
+    Switch from travis to GH actions
+    
+    Also fixes for new C compilator and finding of lua and python libraries
+
+diff --git a/src/tfio.c b/src/tfio.c
+index 151583ebb17cd81e..bbbbd90f7de31134 100644
+--- a/src/tfio.c
++++ b/src/tfio.c
+@@ -45,6 +45,7 @@ static const char RCSid[] = "$Id: tfio.c,v 35004.114 2007/01/13 23:12:39 kkeys E
+ #include "variable.h"	/* getvar() */
+ #include "keyboard.h"	/* keyboard_pos */
+ #include "expand.h"	/* current_command */
++#include "socket.h"	/* main_loop */
+ #include "cmdlist.h"
+ 
+ TFILE *loadfile = NULL; /* currently /load'ing file */
diff --git a/tinyfugue.spec b/tinyfugue.spec
index 6d345a0..68caf0a 100644
--- a/tinyfugue.spec
+++ b/tinyfugue.spec
@@ -3,7 +3,7 @@
 
 Name:           tinyfugue
 Version:        5.0
-Release:        0.105.b8%{?dist}
+Release:        0.107.b8%{?dist}
 Summary:        A MU* client
 License:        GPLv2+
 URL:            http://tinyfugue.sourceforge.net/
@@ -24,6 +24,9 @@ Patch9:         0006-Fix-library-install-path.patch
 Patch10:        0007-Fix-spelling-errors.patch
 Patch11:        0008-Fix-duplicate-world_decl-definitions.patch
 Patch12:        0009-Fix-spelling-error-in-manual-page.patch
+Patch13:        tinyfigue-configure-c99.patch
+Patch14:        tinyfugue-malloc-c99.h
+Patch15:        tinyfugue-tfio-c99.patch
 BuildRequires:  coreutils
 BuildRequires:  gcc
 BuildRequires:  make
@@ -67,6 +70,9 @@ install -D -p -m 644 src/tf.1.nroffman %{buildroot}%{_mandir}/man1/tf.1
 %{_mandir}/man1/tf.1*
 
 %changelog
+* Fri Nov 25 2022 Florian Weimer <fweimer@redhat.com> - 5.0-0.107.b8
+- Port to C99 (mostly)
+
 * Sat Jul 23 2022 Fedora Release Engineering <releng@fedoraproject.org> - 5.0-0.105.b8
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_37_Mass_Rebuild