Deb: Debian 10 building requires package libsm6

debian/control

@@ -3,7 +3,7 @@ Section: x11
 Priority: optional
 Maintainer: Kasm Technologies LLC <info@kasmweb.com>
 Build-Depends: debhelper (>= 11), rsync, libjpeg-dev, libjpeg-dev, libpng-dev,
-  libtiff-dev, libgif-dev, libavcodec-dev, libssl-dev, libgl1, libxfont2
+  libtiff-dev, libgif-dev, libavcodec-dev, libssl-dev, libgl1, libxfont2, libsm6
 Standards-Version: 4.1.3
 Homepage: https://github.com/kasmtech/KasmVNC
 #Vcs-Browser: https://salsa.debian.org/debian/kasmvnc