linux: fix sscanf() overflows reading from /proc
linux: fix sscanf() overflows reading from /proc

Use `"%" PRIu64` and uint64_t for sscanf-ing large values, not `"%lu"`
and unsigned long. The latter can overflow when libuv is a 32 bits
application running on a 64 bits machine.

Fixes: https://github.com/libuv/libuv/issues/2297
PR-URL: https://github.com/libuv/libuv/pull/2305
Reviewed-By: Santiago Gimeno <3f17e29e343c4cf8809fb0970d81d6d8ee88d6b3@gmail.com>
Reviewed-By: Colin Ihrig <838f779c91673db29b8572ea3f54d191d3878ae2@gmail.com>

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso