Wrong "Total size" reported if greater than 2GB

NSIS 2.14 reports wrong size of input stuff if size is
very big:

Using lzma compression.

EXE header size: 46592 / 34304 bytes
Install code: 3805 / 21008 bytes
Install data: 672461458 / -850955931 bytes
Uninstall code+data: 3632 / 12945 bytes
CRC (0x1836FA2D): 4 / 4 bytes

Total size: 672515491 / -850887670 bytes
(-79.0%)

It reports "-850887670" for a 3.2GB input volume. Seems
as an overflow condition. Also, the compression ratio
is distorted.
The generated installer works fine.