Summary:
siying this is a resubmission of #2081 with the 4th commit fixed. From that commit message:

> Note that the previous use of quotes in PLATFORM_{CC,CXX}FLAGS was
incorrect and caused GCC to produce the incorrect define:
>
>  #define ROCKSDB_JEMALLOC -DJEMALLOC_NO_DEMANGLE 1
>
> This was the cause of the Linux build failure on the previous version
of this change.

I've tested this locally, and the Linux build succeeds now.
Closes https://github.com/facebook/rocksdb/pull/2097

Differential Revision: D4839964

Pulled By: siying

fbshipit-source-id: cc51322