Add support for QNX Neutrino. 

This patch incorporates a change to source/common/putil.c 
fetched from upstream. 

In addition, it undefines 'si_value' in source/common/ucnvmbcs.c to 
avoid a collision with 'si_value' defined on some platforms.

Patch by: 
 Eli Fidler <efidler@blackberry.com>, 
 Jeff Rogers <jrogers@blackberry.com>, 
 Cosmin Truta <ctruta@blackberry.com>.

The original CL is at https://codereview.chromium.org/141063008/

README.chromium was slightly updated to refer to the upstream change for
si_value.

TBR=mark@chromium.org
BUG=NONE 
TEST=icu is built properly on qnx. After DEPS roll, net_unittests:*IDN* and base_unittests:*String* all pass on qnx.

Review URL: https://codereview.chromium.org/195973005

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/icu46@257503 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
8 files changed