diff --git a/games/prboom/prboom.SlackBuild b/games/prboom/prboom.SlackBuild
index 9744eb1ba1..546afa13ce 100644
--- a/games/prboom/prboom.SlackBuild
+++ b/games/prboom/prboom.SlackBuild
@@ -22,6 +22,11 @@
 #  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 #  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+# 20220221 bkw: Modified by SlackBuilds.org:
+# - fix 15.0 build.
+# - use "set -e" instead of "|| exit 1" after every command.
+# - do not install useless INSTALL in doc dir.
+
 cd $(dirname $0) ; CWD=$(pwd)
 
 PRGNAM=prboom
@@ -32,15 +37,12 @@ PKGTYPE=${PKGTYPE:-tgz}
 
 if [ -z "$ARCH" ]; then
   case "$( uname -m )" in
-    i?86) ARCH=i486 ;;
+    i?86) ARCH=i586 ;;
     arm*) ARCH=arm ;;
        *) ARCH=$( uname -m ) ;;
   esac
 fi
 
-# If the variable PRINT_PACKAGE_NAME is set, then this script will report what
-# the name of the created package would be, and then exit. This information
-# could be useful to other scripts.
 if [ ! -z "${PRINT_PACKAGE_NAME}" ]; then
   echo "$PRGNAM-$VERSION-$ARCH-$BUILD$TAG.$PKGTYPE"
   exit 0
@@ -50,8 +52,8 @@ TMP=${TMP:-/tmp/SBo}
 PKG=$TMP/package-$PRGNAM
 OUTPUT=${OUTPUT:-/tmp}
 
-if [ "$ARCH" = "i486" ]; then
-  SLKCFLAGS="-O2 -march=i486 -mtune=i686"
+if [ "$ARCH" = "i586" ]; then
+  SLKCFLAGS="-O2 -march=i586 -mtune=i686"
   LIBDIRSUFFIX=""
 elif [ "$ARCH" = "i686" ]; then
   SLKCFLAGS="-O2 -march=i686 -mtune=i686"
@@ -64,6 +66,8 @@ else
   LIBDIRSUFFIX=""
 fi
 
+set -e
+
 rm -rf $PKG
 mkdir -p $TMP $PKG $OUTPUT
 cd $TMP || exit 1
@@ -73,12 +77,14 @@ cd $PRGNAM-$VERSION || exit 1
 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 \
+ -exec chmod 755 {} \+ -o \
  \( -perm 666 -o -perm 664 -o -perm 600 -o -perm 444 -o -perm 440 -o -perm 400 \) \
- -exec chmod 644 {} \;
+ -exec chmod 644 {} \+
 
 # patch thanks to Arch Linux
-patch -p1 < $CWD/libpng-1.4.patch || exit 1
+patch -p1 < $CWD/libpng-1.4.patch
+
+SLKCFLAGS+=" -fcommon"
 
 # --disable-i386-asm fixes the "exit with signal 8" crash on the x86 arch
 # --enable-gl allows to launch game with: prboom -vidmode gl
@@ -94,17 +100,15 @@ CXXFLAGS="$SLKCFLAGS" \
   --docdir=/usr/doc/$PRGNAM-$VERSION \
   --build=$ARCH-slackware-linux \
   --disable-i386-asm \
-  --enable-gl || exit 1
+  --enable-gl
 
-make || exit 1
-make install-strip DESTDIR=$PKG || exit 1
-
-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 $i ; done
+make
+make install-strip DESTDIR=$PKG
+gzip $PKG/usr/man/man*/*
 
 mv $PKG/usr/share/doc $PKG/usr
 mkdir -p $PKG/usr/doc/$PRGNAM-$VERSION
-cp -a TODO INSTALL $PKG/usr/doc/$PRGNAM-$VERSION
+cp -a TODO $PKG/usr/doc/$PRGNAM-$VERSION
 cat $CWD/$PRGNAM.SlackBuild > $PKG/usr/doc/$PRGNAM-$VERSION/$PRGNAM.SlackBuild
 
 mkdir -p $PKG/install