[patch] Define std::experimental::randint etc.

[Jonathan Wakely]

Another piece of the Library Fundamentals v2 TS, as specified by
https://rawgit.com/cplusplus/fundamentals-ts/v2/fundamentals-ts.html#rand.util.randint

Tested powerpc64le-linux, committed to trunk.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: patch.txt
Type: text/x-patch
Size: 6114 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20151113/0c508f11/attachment.bin>