add FB_SINGLE_ARG macro

Test Plan: eyeballed it

@override-unit-failures

Reviewed By: soren@fb.com

FB internal diff: D1125180
fix AtomicHashMap race condition

Summary: AHM::find checks that the returned SimpleRetT index is >= numMapsAllocated_ but that value may have changed and find pick the first element in the next sub map. Use success instead.

@override-unit-failures

Test Plan: unit tests

Reviewed By: delong.j@fb.com

FB internal diff: D1126684
folly: symbolizer: small terse write fix + colorize signal handler output if printing to TTY

Summary:
Detailed output is a bit hard to parse visually. Add some colors for
clarity (clownyness?). Enabled only when printing stack traces from a
signal-handler to TTY.

Also:
- terse output printed empty lines if it could not find a symbol for an address; fixed by printing "(unknown)".
- added a dummy ##Crash## program to test colorization easily

Test Plan: n/a

Reviewed By: tudorb@fb.com

FB internal diff: D1128303
IndexedMemPool - pool allocator tailored for lock-free data structures

Summary:
Instances of IndexedMemPool dynamically allocate and then pool
their element type (T), returning 4-byte integer indices that can be
passed to the pool's operator[] method to access or obtain pointers to
the actual elements.  Once they are constructed, elements are never
destroyed.  These two features are useful for lock-free algorithms.
The indexing behavior makes it easy to build tagged pointer-like-things,
since a large number of elements can be managed using fewer bits than a
full pointer.  The pooling behavior makes it safe to read from T-s even
after they have been recycled

Test Plan:
1. unit tests
2. unit tests using DeterministicSchedule
3. this code is moved from tao/queues where it is in production use

Reviewed By: davejwatson@fb.com

FB internal diff: D1089053
include guard name cleanup for IndexedMemPool

Summary: Include guard had FOLLY_DETAIL_.. even though code is in folly

Test Plan: unit tests

Reviewed By: davejwatson@fb.com

FB internal diff: D1130269

@override-unit-failures
stack_trace_test was broken in debug mode

Summary: A function was getting inlined in opt mode but not in debug mode.

Test Plan: ran test

Reviewed By: philipp@fb.com

FB internal diff: D1130949

@override-unit-failures
test fix only