Patch pcre to pass all tests when compiled with GCC 4.9.

Pcre failed to pass one test when compiled with GCC 4.9.
Patch taken from Fedora, original url is
http://pkgs.fedoraproject.org/cgit/pcre.git/plain/pcre-8.35-Do-not-rely-on-wrapping-signed-integer-while-parsein.patch
Checked on Linux 64-bit with GCC 4.7, 4.8, 4.9, Clang 3.5 - all good.

Fixes https://github.com/JuliaLang/julia/issues/7458
Could the Make rule also depend on `../pcre-gcc49-compile.patch`, and would that force recompilation without having users to do a `make clean`?