diff --git a/development/s9fes/README b/development/s9fes/README
new file mode 100644
index 0000000000..093499d965
--- /dev/null
+++ b/development/s9fes/README
@@ -0,0 +1,3 @@
+S9fES is a mature, portable, and comprehensible interpreter for R4RS Scheme.
+The core interpreter is written in pure ANSI C (C89), so it runs on all
+platforms offering a C compiler.
diff --git a/development/s9fes/patches/Makefile.patch b/development/s9fes/patches/Makefile.patch
new file mode 100644
index 0000000000..ce1ad2e3e9
--- /dev/null
+++ b/development/s9fes/patches/Makefile.patch
@@ -0,0 +1,15 @@
+--- Makefile	2021-06-15 19:09:02.000000000 +0200
++++ Makefile.new	2024-06-15 22:59:28.311511715 +0200
+@@ -3,8 +3,11 @@
+ # By Nils M Holm, 2007-2018
+ # In the public domain
+ 
++# Destination directory for installation.
++DESTDIR=
++
+ # Change at least this line:
+-PREFIX= /u
++PREFIX= $(DESTDIR)/usr
+ 
+ # Base version and Release
+ BASE=		20181115
diff --git a/development/s9fes/patches/s9core.c.patch b/development/s9fes/patches/s9core.c.patch
new file mode 100644
index 0000000000..d4d9291061
--- /dev/null
+++ b/development/s9fes/patches/s9core.c.patch
@@ -0,0 +1,41 @@
+--- s9core.c	2019-04-02 10:45:31.000000000 +0200
++++ s9core.c.new	2024-06-15 22:39:10.836498069 +0200
+@@ -2642,10 +2642,12 @@
+ 
+ int s9_open_input_port(char *path) {
+ 	int	i = s9_new_port();
++	char *res_path = realpath(path, NULL);
+ 
+ 	if (i < 0)
+ 		return -1;
+-	Ports[i] = fopen(path, "r");
++	Ports[i] = fopen(res_path, "r");
++	free(res_path);
+ 	if (Ports[i] == NULL)
+ 		return -1;
+ 	return i;
+@@ -2653,10 +2655,12 @@
+ 
+ int s9_open_output_port(char *path, int append) {
+ 	int	i = s9_new_port();
++	char *res_path = realpath(path, NULL);
+ 
+ 	if (i < 0)
+ 		return -1;
+ 	Ports[i] = fopen(path, append? "a": "w");
++	free(res_path);
+ 	if (Ports[i] == NULL)
+ 		return -1;
+ 	return i;
+@@ -2924,8 +2928,10 @@
+ 	struct magic	m;
+ 	int		image_nodes, image_vcells;
+ 	char		*s;
++	char *res_path = realpath(path, NULL);
+ 
+-	f = fopen(path, "rb");
++	f = fopen(res_path, "rb");
++	free(res_path);
+ 	if (f == NULL)
+ 		return "could not open file";
+ 	if ((s = xfread(&m, sizeof(m), 1, f)) != NULL)
diff --git a/development/s9fes/s9fes.SlackBuild b/development/s9fes/s9fes.SlackBuild
new file mode 100644
index 0000000000..0985f65e04
--- /dev/null
+++ b/development/s9fes/s9fes.SlackBuild
@@ -0,0 +1,110 @@
+#!/bin/bash
+
+# Slackware build script for s9fes
+
+# Copyright 2024 rc_05 <contact@rc-05.com>
+# All rights reserved.
+#
+# Redistribution and use of this script, with or without modification, is
+# permitted provided that the following conditions are met:
+#
+# 1. Redistributions of this script must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR "AS IS" AND ANY EXPRESS OR IMPLIED
+#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
+#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+cd $(dirname $0) ; CWD=$(pwd)
+
+PRGNAM=s9fes
+VERSION=${VERSION:-20181205}
+BUILD=${BUILD:-1}
+TAG=${TAG:-_SBo}
+PKGTYPE=${PKGTYPE:-tgz}
+
+if [ -z "$ARCH" ]; then
+  case "$( uname -m )" in
+    i?86) ARCH=i586 ;;
+    arm*) ARCH=arm ;;
+       *) ARCH=$( uname -m ) ;;
+  esac
+fi
+
+if [ ! -z "${PRINT_PACKAGE_NAME}" ]; then
+  echo "$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE"
+  exit 0
+fi
+
+TMP=${TMP:-/tmp/SBo}
+PKG=$TMP/package-$PRGNAM
+OUTPUT=${OUTPUT:-/tmp}
+
+if [ "$ARCH" = "i586" ]; then
+  SLKCFLAGS="-O2 -march=i586 -mtune=i686"
+  LIBDIRSUFFIX=""
+elif [ "$ARCH" = "i686" ]; then
+  SLKCFLAGS="-O2 -march=i686 -mtune=i686"
+  LIBDIRSUFFIX=""
+elif [ "$ARCH" = "x86_64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  LIBDIRSUFFIX="64"
+elif [ "$ARCH" = "aarch64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  LIBDIRSUFFIX="64"
+else
+  SLKCFLAGS="-O2"
+  LIBDIRSUFFIX=""
+fi
+
+set -e
+
+rm -rf $PKG
+mkdir -p $TMP $PKG $OUTPUT
+cd $TMP
+rm -rf s9
+tar xvf $CWD/$PRGNAM-$VERSION.tgz
+cd s9
+chown -R root:root .
+find -L . \
+ \( -perm 777 -o -perm 775 -o -perm 750 -o -perm 711 -o -perm 555 \
+  -o -perm 511 \) -exec chmod 755 {} \; -o \
+ \( -perm 666 -o -perm 664 -o -perm 640 -o -perm 600 -o -perm 444 \
+  -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \;
+
+# For this oneliner a patch is not needed.
+sed -i "s_:/usr/local/share/s9fes_:/usr/share/s9fes_" s9.c
+
+for p in `ls $CWD/patches`; do
+    patch < $CWD/patches/$p
+done
+
+make all
+make install-s9 DESTDIR=$PKG
+
+rm -f $PKG/{,usr/}lib${LIBDIRSUFFIX}/*.la
+
+find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \
+  | cut -f 1 -d : | xargs strip --strip-unneeded 2> /dev/null || true
+
+find $PKG/usr/man -type f -exec gzip -9 {} \;
+for i in $( find $PKG/usr/man -type l ) ; do ln -s $( readlink $i ).gz $i.gz ; rm $i ; done
+
+mkdir -p $PKG/usr/doc/$PRGNAM-$VERSION
+cp -a \
+  HISTORY LICENSE MASCOT.png PREHISTORY README README.s9core TODO \
+  $PKG/usr/doc/$PRGNAM-$VERSION
+cat $CWD/$PRGNAM.SlackBuild > $PKG/usr/doc/$PRGNAM-$VERSION/$PRGNAM.SlackBuild
+
+mkdir -p $PKG/install
+cat $CWD/slack-desc > $PKG/install/slack-desc
+
+cd $PKG
+/sbin/makepkg -l y -c n $OUTPUT/$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE
diff --git a/development/s9fes/s9fes.info b/development/s9fes/s9fes.info
new file mode 100644
index 0000000000..f4d39cad76
--- /dev/null
+++ b/development/s9fes/s9fes.info
@@ -0,0 +1,10 @@
+PRGNAM="s9fes"
+VERSION="20181205"
+HOMEPAGE="https://t3x.org/s9fes/"
+DOWNLOAD="https://t3x.org/s9fes/s9fes-20181205.tgz"
+MD5SUM="1a9c137c40e3c74cf892e24366ea2d93"
+DOWNLOAD_x86_64=""
+MD5SUM_x86_64=""
+REQUIRES="%README%"
+MAINTAINER="rc_05"
+EMAIL="contact@rc-05.com"
diff --git a/development/s9fes/slack-desc b/development/s9fes/slack-desc
new file mode 100644
index 0000000000..677e8caf18
--- /dev/null
+++ b/development/s9fes/slack-desc
@@ -0,0 +1,19 @@
+# HOW TO EDIT THIS FILE:
+# The "handy ruler" below makes it easier to edit a package description.
+# Line up the first '|' above the ':' following the base package name, and
+# the '|' on the right side marks the last column you can put a character in.
+# You must make exactly 11 lines for the formatting to be correct.  It's also
+# customary to leave one space after the ':' except on otherwise blank lines.
+
+     |-----handy-ruler------------------------------------------------------|
+s9fes: s9fes (Scheme 9 from Outer Space)
+s9fes:
+s9fes: S9fES is a mature, portable, and comprehensible interpreter for
+s9fes: R4RS Scheme.
+s9fes:
+s9fes: The core interpreter is written in pure ANSI C (C89),
+s9fes: so it runs on all platforms offering a C compiler.
+s9fes:
+s9fes: Homepage: https://t3x.org/s9fes/
+s9fes:
+s9fes: