Fix build failure with GCC 5

Patch applied in Debian to solve FTBFS with the GCC's new
version. The original bug report is available here:
- https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=777997

Fix FTBFS on most Debian architectures

Fixes Debian#773786 and enables support on non-ARM,
Non-x86, and kFreeBSD architectures.

JSON names/keys are now quoted to be strings in output

JSON names(keys) output are now strings (double-quoted as per http://tools.ietf.org/html/rfc7158#page-6)

unicornscan compatible output for tcp scans