--- a/zstd.SlackBuild	2021-01-20 20:16:44.524010682 +0200
+++ b/zstd.SlackBuild	2021-02-04 18:14:54.843806735 +0200
@@ -63,6 +63,14 @@
   SLKCFLAGS="-O2 -fPIC"
   SLKLDFLAGS="-L/usr/lib64"
   LIBDIRSUFFIX="64"
+elif [ "$ARCH" = "aarch64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  SLKLDFLAGS="-L/usr/lib64"
+  LIBDIRSUFFIX="64"
+elif [ "$ARCH" = "riscv64" ]; then
+  SLKCFLAGS="-O2 -fPIC"
+  SLKLDFLAGS="-L/usr/lib64"
+  LIBDIRSUFFIX="64"
 elif [ "$ARCH" = "armv7hl" ]; then
   SLKCFLAGS="-O2 -march=armv7-a -mfpu=vfpv3-d16"
   SLKLDFLAGS=""