emu: extract options to (ignored) emu.config

.gitignore

@@ -1,2 +1,3 @@
 _attic/
 vendor/src/
+emu.config

emu.sh

@@ -1,9 +1,14 @@
 #!/bin/bash
 
-ARGS="${ARGS:--O0 -X heapsize=100000}"
+source emu.config 2>/dev/null
+
+OPTLEVEL="${OPTLEVEL:-0}"
+HEAPSIZE="${HEAPSIZE:-100000}"
 MAIN="${MAIN:-main.py}"
 BROWSER="${BROWSER:-chromium}"
 
+ARGS="-O${OPTLEVEL} -X heapsize=${HEAPSIZE}"
+
 cd `dirname $0`/src
 
 case "$1" in