change build system to CMake and use SDL3 for everything

libs/SDL3/build-scripts/update-copyright.sh

@@ -0,0 +1,15 @@
+#!/bin/sh
+
+if [ "$SED" = "" ]; then
+    if type gsed >/dev/null; then
+        SED=gsed
+    else
+        SED=sed
+    fi
+fi
+
+find . -type f \
+| grep -v \.git                                 \
+| while read file; do                           \
+    LC_ALL=C $SED -b -i "s/\(.*Copyright.*\)[0-9]\{4\}\( *Sam Lantinga\)/\1`date +%Y`\2/" "$file"; \
+done