Created attachment 402876 [details]
This is an upstream issue. I'm unaware if upstream is aware of the issue. All versions in tree including 9999 but excluding 2.13 are affected.
To detect the size of off_t, autoconf does a bitshift of 62 when dealing with both 64bit and 32 bit code. This is handled appropriately by shifting by 31 twice. The attached patch is from Debian.
it does not look like Debian notified upstream. this really should be sent there first.
also worth noting: any package using 32bit off_t in Gentoo is broken and needs to be fixed in which case this report is mostly moot :). see bug 471102 for details.
Just to do it formally have you sent this / notified upstream? Otehr potential viewers will also know.