Revert "THRIFT-2045: C++ compiler warning and build cleanup"

This reverts commit 282e440c6de219b7b8f32b01cc7eb599f534f33f.

This change had unintended autoconf side effects.
THRIFT-2031: Make SO_KEEPALIVE configurable for C++ lib
Client: cpp
Patch: Ben Craig
THRIFT-2027: Minor 64-bit and NOMINMAX issues in C++ library
Client: cpp
Patch: Ben Craig
THRIFT-1751: definition of increase_max_fds doesn't compile when
HAVE_SYS_RESOURCE_H is not defined
Client: cpp
Patch: Ben Craig
THRIFT-2021: Improve large binary protocol string performance
Client: cpp
Patch: Ben Craig
THRIFT-2019: Writing on a disconnected socket on Mac causes SIG PIPE
Client: cpp
Patch: Ben Craig