[NaCl SDK] Enable linux host build for nacl_io and nacl_io_tests.

native_client_sdk/src/libraries/nacl_io/mount_node_http.cc

Index: native_client_sdk/src/libraries/nacl_io/mount_node_http.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc b/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc
index d6355ad81b91696f545653779b095215a1b1ea95..5a65d413de36d04fe4e7078f97c6ee8ce48aa517 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_http.cc
@@ -101,9 +101,9 @@ bool ParseContentRange(const StringMap_t& headers,
 
   // The key should look like "bytes ##-##/##" or "bytes ##-##/*". The last
   // value is the entity length, which can potentially be * (i.e. unknown).
-  int read_start_int;
-  int read_end_int;
-  int entity_length_int;
+  size_t read_start_int;
+  size_t read_end_int;
+  size_t entity_length_int;
   int result = sscanf(iter->second.c_str(),
                       "bytes %" SCNuS "-%" SCNuS "/%" SCNuS,
                       &read_start_int,