diff --git a/libraries/gf2x/README b/libraries/gf2x/README
index 43795c2717..5667081a55 100644
--- a/libraries/gf2x/README
+++ b/libraries/gf2x/README
@@ -1,3 +1,7 @@
 gf2x is a C/C++ software package containing routines for fast
 arithmetic in GF(2)[x] (multiplication, squaring, GCD) and searching
 for irreducible/primitive trinomials.
+
+gf2x requires a CPU with SSE2 support. All x86_64 CPUs are OK, and
+most 32-bit x86 CPUs still in use in 2022 are OK. If in doubt, run
+e.g. "grep sse2 /proc/cpuinfo" to find out.
diff --git a/libraries/gf2x/gf2x.SlackBuild b/libraries/gf2x/gf2x.SlackBuild
index 631a3d99be..fa7262721d 100644
--- a/libraries/gf2x/gf2x.SlackBuild
+++ b/libraries/gf2x/gf2x.SlackBuild
@@ -22,11 +22,15 @@
 #  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 #  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+# 20220419 bkw: Modified by SlackBuilds.org, BUILD=4:
+# - add note to README about SSE2.
+# - remove empty/useless docs from doc dir.
+
 cd $(dirname $0) ; CWD=$(pwd)
 
 PRGNAM=gf2x
 VERSION=${VERSION:-1.3.0}
-BUILD=${BUILD:-3}
+BUILD=${BUILD:-4}
 TAG=${TAG:-_SBo}
 PKGTYPE=${PKGTYPE:-tgz}
 
@@ -38,9 +42,6 @@ if [ -z "$ARCH" ]; then
   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
@@ -77,13 +78,14 @@ cd $PRGNAM-$VERSION
 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 \
+  -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 {} \;
+  -o -perm 440 -o -perm 400 \) -exec chmod 644 {} \+
 
-CFLAGS="$SLKCFLAGS -msse2" \
+SLKCFLAGS+=" -msse2"
 autoreconf -fi
 rm -Rf autom4te.cache
+CFLAGS="$SLKCFLAGS" \
 CXXFLAGS="$SLKCFLAGS" \
 ./configure \
   --prefix=/usr \
@@ -97,13 +99,10 @@ CXXFLAGS="$SLKCFLAGS" \
   --build=$ARCH-slackware-linux
 
 make
-make install DESTDIR=$PKG
-
-find $PKG -print0 | xargs -0 file | grep -e "executable" -e "shared object" | grep ELF \
-  | cut -f 1 -d : | xargs strip --strip-unneeded 2> /dev/null || true
+make install-strip DESTDIR=$PKG
 
 mkdir -p $PKG/usr/doc/$PRGNAM-$VERSION
-cp -a AUTHORS BUGS COPYING ChangeLog INSTALL NEWS README TODO $PKG/usr/doc/$PRGNAM-$VERSION
+cp -a AUTHORS BUGS COPYING NEWS README TODO $PKG/usr/doc/$PRGNAM-$VERSION
 cat $CWD/$PRGNAM.SlackBuild > $PKG/usr/doc/$PRGNAM-$VERSION/$PRGNAM.SlackBuild
 
 rm -f $PKG/usr/lib*/*.la