Fix "Cannot allocate memory" on mmap of files bigger than 2GiB.

https://github.com/rc0/mairix/issues/12

diff -ruN t/mairix-0.22/mairix.h mairix/mairix-0.22/mairix.h
--- t/mairix-0.22/mairix.h  2010-06-05 14:41:10.000000000 -0700
+++ mairix/mairix-0.22/mairix.h 2015-07-08 13:33:06.678718524 -0700
@@ -327,8 +327,8 @@
   DTR8_BAD_ATTACHMENT /* corrupt attachment (e.g. no body part) */
 };
 struct rfc822 *data_to_rfc822(struct msg_src *src, char *data, int length, enum data_to_rfc822_error *error);
-void create_ro_mapping(const char *filename, unsigned char **data, int *len);
-void free_ro_mapping(unsigned char *data, int len);
+void create_ro_mapping(const char *filename, unsigned char **data, size_t *len);
+void free_ro_mapping(unsigned char *data, size_t len);
 char *format_msg_src(struct msg_src *src);

 /* In tok.c */
diff -ruN t/mairix-0.22/mbox.c mairix/mairix-0.22/mbox.c
--- t/mairix-0.22/mbox.c    2010-06-05 14:41:10.000000000 -0700
+++ mairix/mairix-0.22/mbox.c   2015-07-08 13:32:45.126280861 -0700
@@ -816,7 +816,7 @@
         mb->n_old_msgs_valid = mb->n_msgs;
       } else {
         unsigned char *va;
-        int len;
+        size_t len;
         create_ro_mapping(mb->path, &va, &len);
         if (va) {
           rescan_mbox(mb, (char *) va, len);
@@ -852,7 +852,7 @@
   int any_new = 0;
   int N;
   unsigned char *va;
-  int valen;
+  size_t valen;
   enum data_to_rfc822_error error;

   for (i=0; i<db->n_mboxen; i++) {
diff -ruN t/mairix-0.22/rfc822.c mairix/mairix-0.22/rfc822.c
--- t/mairix-0.22/rfc822.c  2010-06-05 14:41:10.000000000 -0700
+++ mairix/mairix-0.22/rfc822.c 2015-07-08 13:30:59.388133879 -0700
@@ -1250,7 +1250,7 @@
 }
 #endif /* USE_GZIP_MBOX || USE_BZIP_MBOX */

-void create_ro_mapping(const char *filename, unsigned char **data, int *len)/*{{{*/
+void create_ro_mapping(const char *filename, unsigned char **data, size_t *len)/*{{{*/
 {
   struct stat sb;
   int fd;
@@ -1371,7 +1371,7 @@
   data_alloc_type = ALLOC_MMAP;
 }
 /*}}}*/
-void free_ro_mapping(unsigned char *data, int len)/*{{{*/
+void free_ro_mapping(unsigned char *data, size_t len)/*{{{*/
 {
   int r;

@@ -1399,7 +1399,7 @@
 /*}}}*/
 struct rfc822 *make_rfc822(char *filename)/*{{{*/
 {
-  int len;
+  size_t len;
   unsigned char *data;
   struct rfc822 *result;

diff -ruN t/mairix-0.22/search.c mairix/mairix-0.22/search.c
--- t/mairix-0.22/search.c  2010-06-05 14:41:10.000000000 -0700
+++ mairix/mairix-0.22/search.c 2015-07-08 13:32:25.809888610 -0700
@@ -667,7 +667,7 @@
 static void append_file_to_mbox(const char *path, FILE *out)/*{{{*/
 {
   unsigned char *data;
-  int len;
+  size_t len;
   create_ro_mapping(path, &data, &len);
   if (data) {
     fprintf(out, "From mairix@mairix Mon Jan  1 12:34:56 1970\n");
@@ -683,8 +683,8 @@

 static void get_validated_mbox_msg(struct read_db *db, int msg_index,/*{{{*/
                                    int *mbox_index,
-                                   unsigned char **mbox_data, int *mbox_len,
-                                   unsigned char **msg_data,  int *msg_len)
+                                   unsigned char **mbox_data, size_t *mbox_len,
+                                   unsigned char **msg_data,  size_t *msg_len)
 {
   /* msg_data==NULL if checksum mismatches */
   unsigned char *start;
@@ -715,7 +715,7 @@
 {
   /* Need to common up code with try_copy_to_path */
   unsigned char *mbox_start, *msg_start;
-  int mbox_len, msg_len;
+  size_t mbox_len, msg_len;
   int mbox_index;

   get_validated_mbox_msg(db, msg_index, &mbox_index, &mbox_start, &mbox_len, &msg_start, &msg_len);
@@ -735,7 +735,7 @@
 static void try_copy_to_path(struct read_db *db, int msg_index, char *target_path)/*{{{*/
 {
   unsigned char *data;
-  int mbox_len, msg_len;
+  size_t mbox_len, msg_len;
   int mbi;
   FILE *out;
   unsigned char *start;