--- a/fftw.SlackBuild	2021-02-13 03:19:35.871579048 +0200
+++ b/fftw.SlackBuild	2021-02-13 03:20:24.787551164 +0200
@@ -63,6 +63,14 @@
   SLKCFLAGS="-O2 -fPIC"
   LIBDIRSUFFIX="64"
   SIMD="--enable-sse2 --enable-avx"
+elif [ "$ARCH" = "aarch64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  LIBDIRSUFFIX="64"
+  SIMD=""
+elif [ "$ARCH" = "riscv64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  LIBDIRSUFFIX="64"
+  SIMD=""
 else
   SLKCFLAGS="-O2"
   LIBDIRSUFFIX=""
@@ -142,6 +150,11 @@
 make install-strip DESTDIR=$PKG || exit 1
 make clean
 
+#
+# Not for ARM, as we don't have the quadmath library in gcc.
+#    --enable-quad-precision \
+#
+
 # compile libfftw3q
 ./configure \
     --prefix=/usr \
@@ -155,7 +168,6 @@
     --disable-static \
     --enable-threads \
     --enable-openmp \
-    --enable-quad-precision \
     --build=$ARCH-slackware-linux || exit 1
 
 make $NUMJOBS || make || exit 1