Add core cmocka framework

Initial integration with cmocka.

The intent is to first apply this to the xrdp unit tests, but until
something uses it directly we'll hold off on updating the Makefile.

scripts/install_xrdp_build_dependencies_with_apt.sh

@@ -59,6 +59,7 @@ PACKAGES=" \
     nasm \
     pkg-config \
     check \
+    libcmocka-dev
     "
 
 # libfreetype-dev package was renamed from libfreetype6-dev in older
@@ -86,7 +87,7 @@ in
                 ;;
             max)
                 PACKAGES="$PACKAGES \
-                    $PACKAGES_AMD64_MIN
+                    $PACKAGES_AMD64_MIN \
                     $LIBFREETYPE_DEV \
                     libfuse-dev \
                     libjpeg-dev \
@@ -139,6 +140,7 @@ in
 esac
 
 apt-get update
+apt-get upgrade
 apt-get -yq \
     --no-install-suggests \
     --no-install-recommends \