Add missing files, helper scripts and .gitignore

.gitignore

@@ -0,0 +1,15 @@
+Chf/mt_build/
+Chf/st_build/
+Makefile
+Makefile.bak
+Saturn
+cpu
+hdw
+mod
+pack
+pack._man
+saturn
+saturn._man
+saturn.cat
+stateDir.gwh_run48/
+*.o

gwh_build.sh

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+#!/bin/bash -eu
+
+make clean
+xmkmf
+touch saturn.man pack.man
+make

gwh_run48.sh

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+#!/bin/bash -eu
+
+STATEDIR=./stateDir.gwh_run48
+mkdir -p $STATEDIR
+
+if [ ! -e $STATEDIR/gxrom-r ]; then
+    (cd $STATEDIR
+     wget -c https://www.hpcalc.org/hp48/pc/emulators/gxrom-r.zip -O gxrom-r.zip
+     unzip gxrom-r.zip
+     rm gxrom-r.zip
+    )
+fi
+RAM=ram
+if [ ! -e $STATEDIR/ram ]; then
+    RAM="-reset"
+fi
+
+./run_saturn -face hp48 -hw hp48 -stateDir $STATEDIR -rom gxrom-r $RAM