Move lexerstr to main py directory (everyone uses it).
diff --git a/py/lexerunix.c b/py/lexerunix.c
index 5336610..225ed20 100644
--- a/py/lexerunix.c
+++ b/py/lexerunix.c
@@ -6,42 +6,10 @@
 #include "misc.h"
 #include "mpconfig.h"
 #include "lexer.h"
+#include "lexerunix.h"
 
 #if MICROPY_ENABLE_LEXER_UNIX
 
-typedef struct _str_buf_t {
-    bool free;                  // free src_beg when done
-    const char *src_beg;        // beginning of source
-    const char *src_cur;        // current location in source
-    const char *src_end;        // end (exclusive) of source
-} str_buf_t;
-
-unichar str_buf_next_char(str_buf_t *sb) {
-    if (sb->src_cur < sb->src_end) {
-        return *sb->src_cur++;
-    } else {
-        return MP_LEXER_CHAR_EOF;
-    }
-}
-
-void str_buf_free(str_buf_t *sb) {
-    if (sb) {
-        if (sb->free) {
-            m_del(char, (char*)sb->src_beg, 0 /* unknown size of src_beg */);
-        }
-        m_del_obj(str_buf_t, sb);
-    }
-}
-
-mp_lexer_t *mp_lexer_new_from_str_len(const char *src_name, const char *str, uint len, bool free_str) {
-    str_buf_t *sb = m_new(str_buf_t, 1);
-    sb->free = free_str;
-    sb->src_beg = str;
-    sb->src_cur = str;
-    sb->src_end = str + len;
-    return mp_lexer_new(src_name, sb, (mp_lexer_stream_next_char_t)str_buf_next_char, (mp_lexer_stream_close_t)str_buf_free);
-}
-
 mp_lexer_t *mp_lexer_new_from_file(const char *filename) {
     int fd = open(filename, O_RDONLY);
     if (fd < 0) {
@@ -59,7 +27,7 @@
         return NULL;
     }
 
-    return mp_lexer_new_from_str_len(filename, data, size, true);
+    return mp_lexer_new_from_str_len(filename, data, size, size);
 }
 
 /******************************************************************************/