RFA: v3 PATCH to add on_quick_exit/quick_exit to std

[Dominique Dhumieres]

The test fails on x86_64-apple-darwin10 with

FAIL: 18_support/quick_exit/quick_exit.cc (test for excess errors)
Excess errors:
/opt/gcc/work/libstdc++-v3/testsuite/18_support/quick_exit/quick_exit.cc:36:3: error: 'at_quick_exit' is not a member of 'std'
/opt/gcc/work/libstdc++-v3/testsuite/18_support/quick_exit/quick_exit.cc:38:3: error: 'quick_exit' is not a member of 'std'

UNRESOLVED: 18_support/quick_exit/quick_exit.cc compilation failed to produce executable

TIA

Dominique