Make strtosz() return int64_t instead of ssize_t

strtosz() needs to return a 64 bit type even on 32 bit
architectures. Otherwise qemu-img will fail to create disk
images >= 2GB

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/cutils.c b/cutils.c
index 7984bc1..4d2e27c 100644
--- a/cutils.c
+++ b/cutils.c
@@ -291,9 +291,9 @@
  * value must be terminated by whitespace, ',' or '\0'. Return -1 on
  * error.
  */
-ssize_t strtosz_suffix(const char *nptr, char **end, const char default_suffix)
+int64_t strtosz_suffix(const char *nptr, char **end, const char default_suffix)
 {
-    ssize_t retval = -1;
+    int64_t retval = -1;
     char *endptr, c, d;
     int mul_required = 0;
     double val, mul, integral, fraction;
@@ -365,7 +365,7 @@
             goto fail;
         }
     }
-    if ((val * mul >= ~(size_t)0) || val < 0) {
+    if ((val * mul >= INT64_MAX) || val < 0) {
         goto fail;
     }
     retval = val * mul;
@@ -378,7 +378,7 @@
     return retval;
 }
 
-ssize_t strtosz(const char *nptr, char **end)
+int64_t strtosz(const char *nptr, char **end)
 {
     return strtosz_suffix(nptr, end, STRTOSZ_DEFSUFFIX_MB);
 }