diff --git a/polymer/eduke32/source/lunatic/control.lua b/polymer/eduke32/source/lunatic/control.lua
index 4287f3bf1..0cf557922 100644
--- a/polymer/eduke32/source/lunatic/control.lua
+++ b/polymer/eduke32/source/lunatic/control.lua
@@ -1990,7 +1990,7 @@ local function gamearray_file_common(qnum, writep)
     local f, errmsg
 
     if (writep) then
-        f, errmsg = io.open(fn)
+        f, errmsg = io.open(fn, "rb")
         if (f == nil) then
             -- file, numints, isnewgar, filename
             return nil, nil, true, fn
@@ -2101,7 +2101,7 @@ local gamearray_methods = {
             error("refusing to overwrite a file not created by a previous `writearraytofile'", 2)
         end
 
-        local f, errmsg = io.open(fn, "w+")
+        local f, errmsg = io.open(fn, "wb+")
         if (f == nil) then
             error([[failed opening "%s" for writing: %s]], fn, errmsg, 3)
         end
diff --git a/polymer/eduke32/source/lunatic/defs_common.lua b/polymer/eduke32/source/lunatic/defs_common.lua
index 6fbc34227..ee81f4331 100644
--- a/polymer/eduke32/source/lunatic/defs_common.lua
+++ b/polymer/eduke32/source/lunatic/defs_common.lua
@@ -23,6 +23,7 @@ ffi.cdef "const char **g_argv;"
 --     dump: load LuaJIT's 'dump' module, printing generated IR/machine code
 --           (env var: LUAJIT_DUMPFILE)
 --   strict: catch various conditions that may indicate an logical error
+-- TODO for strict: actor[], spriteext[], per-actor gamevars
 local debug_flags = {}
 local IS_DEBUG_FLAG = {
     diag=true, nojit=true, traces=true, dump=true,
diff --git a/polymer/eduke32/source/lunatic/test/gamearray.con b/polymer/eduke32/source/lunatic/test/gamearray.con
new file mode 100644
index 000000000..fcf0bb5e4
--- /dev/null
+++ b/polymer/eduke32/source/lunatic/test/gamearray.con
@@ -0,0 +1,135 @@
+// Test for gamearrays / their persistence.
+// Doesn't run in C-CON because redefinequote/qsprintf error out when passed a
+// non-allocated quote as destination.
+
+define QWESZ 10
+define ASDSZ 12
+
+define MAXTILES 30720  // XXX
+
+gamearray qwe QWESZ
+gamearray asd ASDSZ
+
+define NEWQWESZ 9
+define NEWASDSZ 14
+
+gamearray qwe1 1  // should auto-resize when reading in
+gamearray asd1 NEWASDSZ
+
+gamevar qwesz 0 0
+gamevar asdsz 0 0
+
+// Test gamevars that are named like Lua keywords.
+gamevar local 0 0
+
+gamevar i 0 0
+gamevar tmp 0 0
+
+definequote 400 LTEST_QWE_ARRAY.bin
+definequote 401 LTEST_ASD_ARRAY.bin
+
+definequote 505 tile y sizes: 0:%d 1:%d 2:%d 3:%d 4:%d 5:%d 6:%d 7:%d 8:%d
+definequote 506 1: 0x0a0a0d0d==168430861 ? %d
+definequote 507 2: 0x0a0a0d0d==168430861 ? %d
+
+state error
+    setactor[-1].cstat 0
+ends
+
+onevent EVENT_ENTERLEVEL
+    setvar i 0
+    whilevarn i QWESZ
+    {
+        setarray qwe[i] i
+        addvar i 1
+    }
+
+    // Test nested array syntax:
+    setarray qwe[qwe[5]] 0
+
+    // qwe[] now:
+    // 0 1 2 3 4 0 6 7 8 9
+
+    setvar i 0
+    whilevarn i ASDSZ
+    {
+        setvarvar tmp i
+        addvar tmp 100
+        setarray asd[i] tmp
+        setvarvar local tmp
+        addvar i 1
+    }
+
+    copy qwe[4] /*->*/ asd[3] 3
+
+    setarray asd[4] 0x0a0a0d0d
+
+    // asd[] now:
+    // 100 101 102 4 0x0a0a0d0d 6 106 107 108 109 110 111
+
+    qsprintf 506 506 asd[4]
+    userquote 506
+
+    resizearray qwe NEWQWESZ  // shrink
+    resizearray asd NEWASDSZ  // grow
+
+    writearraytofile qwe 400
+    writearraytofile asd 401
+
+    readarrayfromfile qwe1 400
+    readarrayfromfile asd1 401
+
+    qsprintf 507 507 asd[4]
+    userquote 507
+
+    ifvarn asd[4] 0x0a0a0d0d state error
+
+    // test array sizes
+    getarraysize qwe qwesz
+    getarraysize asd asdsz
+
+    ifvarn qwesz NEWQWESZ state error
+    ifvarn asdsz NEWASDSZ state error
+
+    // test array sizes with *1 arrays
+    getarraysize qwe1 qwesz
+    getarraysize asd1 asdsz
+
+    ifvarn qwesz NEWQWESZ state error
+    ifvarn asdsz NEWASDSZ state error
+
+    redefinequote 500 [%d]: qwe=%d, qwe1=%d, asd=%d, asd1=%d
+    setvar i 0
+    whilevarvarn i -1
+    {
+        ifvarl i NEWQWESZ
+            qsprintf 501 500 i qwe[i] qwe1[i] asd[i] asd1[i]
+        else
+            qsprintf 501 500 i -1 -1 asd[i] asd1[i]
+        userquote 501
+        addvar i 1
+
+        ifvare i NEWASDSZ
+            setvar i -1
+    }
+
+    redefinequote 500 MUST REACH
+    userquote 500
+
+    setvar i 120
+    modvar i 25
+    addlogvar i
+
+
+    //// Test system gamearrays
+
+    getarraysize tilesizx qwesz
+    ifvarn qwesz MAXTILES state error
+
+    copy tilesizy[0] /*->*/ qwe[0] 9
+    qsprintf 505 505 qwe[0] qwe[1] qwe[2] qwe[3] qwe[4] qwe[5] qwe[6] qwe[7] qwe[8]
+    userquote 505
+
+    // Must give a translation error:
+//    resizearray tilesizy 100
+endevent
diff --git a/polymer/eduke32/source/lunatic/util/mapdiff.sh b/polymer/eduke32/source/lunatic/util/mapdiff.sh
index f3354ae08..7fdcfe946 100755
--- a/polymer/eduke32/source/lunatic/util/mapdiff.sh
+++ b/polymer/eduke32/source/lunatic/util/mapdiff.sh
@@ -5,11 +5,13 @@ CMD="/usr/bin/env luajit ./map2text.lua"
 
 opt=""
 
-if [ `uname -s` != "Linux" ]; then
-    # I think 'tempfile' isn't in POSIX. Feel free to use 'mktemp' or something
-    # but absolutely test it before.
-    echo "This helper script is for Linux only."
-    return 1
+# Name of the 'tempfile' or 'mktemp' command (or full path).
+tempfile_cmd=tempfile
+
+tempfile_path=`which "$tempfile_cmd"`
+if [ -z "$tempfile_path" ]; then
+    echo "Error: tempfile_cmd ($tempfile_cmd) must be the name of existing 'tempfile' or 'mktemp' executable."
+    exit 1
 fi
 
 if [ "$1" = "-c" -o "$1" = "-C" ]; then
@@ -22,8 +24,18 @@ if [ -z "$1" -o -z "$2" ]; then
     exit 1
 fi
 
-tf1=`tempfile`
-tf2=`tempfile`
+tf1=`"$tempfile_cmd"`
+if [ -z "$tf1" ]; then
+    echo Failed creating temp file
+    exit 2
+fi
+
+tf2=`"$tempfile_cmd"`
+if [ -z "$tf2" ]; then
+    rm "$tf1"
+    echo Failed creating temp file
+    exit 2
+fi
 
 $CMD $opt "$1" > "$tf1"
 $CMD $opt "$2" > "$tf2"