cjson calls isinf, but some Solaris versions don't have isinf
even with the attempted fix we have in deps/Makefile.
We can harmlessly include the Redis solarisfixes.h header to
give cjson proper isinf.
Note: cjson has a compile-time setting for using their own defined
isinf, but the Redis definition in solarisfixes.h is more complete.
Fixes antirez#1620