py: Add qstr cfg capability; generate QSTR_NULL and QSTR_ from script.
diff --git a/py/makeqstrdata.py b/py/makeqstrdata.py
index f5ce277..c8e998e 100644
--- a/py/makeqstrdata.py
+++ b/py/makeqstrdata.py
@@ -40,12 +40,25 @@
 
 def do_work(infiles):
     # read the qstrs in from the input files
+    qcfgs = {}
     qstrs = {}
     for infile in infiles:
         with open(infile, 'rt') as f:
             for line in f:
+                line = line.strip()
+
+                # is this a config line?
+                match = re.match(r'^QCFG\((.+), (.+)\)', line)
+                if match:
+                    value = match.group(2)
+                    if value[0] == '(' and value[-1] == ')':
+                        # strip parenthesis from config value
+                        value = value[1:-1]
+                    qcfgs[match.group(1)] = value
+                    continue
+
                 # is this a QSTR line?
-                match = re.match(r'^Q\((.+)\)$', line.strip())
+                match = re.match(r'^Q\((.*)\)$', line)
                 if not match:
                     continue
 
@@ -63,11 +76,13 @@
     # process the qstrs, printing out the generated C header file
     print('// This file was automatically generated by makeqstrdata.py')
     print('')
+    # add NULL qstr with no hash or data
+    print('QDEF(MP_QSTR_NULL, (const byte*)"\\x00\\x00\\x00\\x00" "")')
     for order, ident, qstr in sorted(qstrs.values(), key=lambda x: x[0]):
         qhash = compute_hash(qstr)
         qlen = len(qstr)
         qdata = qstr.replace('"', '\\"')
-        print('Q(%s, (const byte*)"\\x%02x\\x%02x\\x%02x\\x%02x" "%s")' % (ident, qhash & 0xff, (qhash >> 8) & 0xff, qlen & 0xff, (qlen >> 8) & 0xff, qdata))
+        print('QDEF(MP_QSTR_%s, (const byte*)"\\x%02x\\x%02x\\x%02x\\x%02x" "%s")' % (ident, qhash & 0xff, (qhash >> 8) & 0xff, qlen & 0xff, (qlen >> 8) & 0xff, qdata))
 
     return True
 
diff --git a/py/qstr.c b/py/qstr.c
index 44c69dc..bb31a08 100644
--- a/py/qstr.c
+++ b/py/qstr.c
@@ -75,11 +75,9 @@
     10,                 // set so that the first dynamically allocated pool is twice this size; must be <= the len (just below)
     MP_QSTR_number_of,  // corresponds to number of strings in array just below
     {
-        (const byte*) "\0\0\0\0", // invalid/no qstr has empty data
-        (const byte*) "\x05\x15\0\0", // empty qstr with hash=5381=0x1505
-#define Q(id, str) str,
+#define QDEF(id, str) str,
 #include "genhdr/qstrdefs.generated.h"
-#undef Q
+#undef QDEF
     },
 };
 
diff --git a/py/qstr.h b/py/qstr.h
index d5ec1fe..776c2ab 100644
--- a/py/qstr.h
+++ b/py/qstr.h
@@ -35,12 +35,11 @@
 // Note: it would be possible to define MP_QSTR_xxx as qstr_from_str_static("xxx")
 // for qstrs that are referenced this way, but you don't want to have them in ROM.
 
+// first entry in enum will be MP_QSTR_NULL=0, which indicates invalid/no qstr
 enum {
-    MP_QSTR_NULL = 0, // indicates invalid/no qstr
-    MP_QSTR_ = 1, // the empty qstr
-#define Q(id, str) MP_QSTR_##id,
+#define QDEF(id, str) id,
 #include "genhdr/qstrdefs.generated.h"
-#undef Q
+#undef QDEF
     MP_QSTR_number_of,
 };
 
diff --git a/py/qstrdefs.h b/py/qstrdefs.h
index 04890a8..514116b 100644
--- a/py/qstrdefs.h
+++ b/py/qstrdefs.h
@@ -29,6 +29,10 @@
 // All the qstr definitions in this file are available as constants.
 // That is, they are in ROM and you can reference them simply as MP_QSTR_xxxx.
 
+// qstr configuration passed to makeqstrdata.py of the form QCFG(key, value)
+//QCFG(somekey, somevalue)
+
+Q()
 Q(*)
 Q(__build_class__)
 Q(__class__)