Investigate suggested performance improvements from PAE team

Tim Cook from the PAE team has made some suggestions on possible performance improvements we could try when running Drizzle benchmarks. Need to investigate and try these out to see what sorts of gain this would provide us.

From Tim:
I have built Drizzle on Solaris/SPARC and tested my ptr_compare* change. I see a smaller but definite improvement, so I recommend the patch I have attached.

I have re-worked it to use TARGET_OS_SOLARIS. I'm leaving the ball in your court on whether you want to test this change on Linux.

There is one other change required - it would be best if "-fno-builtin-memcmp" is used in the build when GCC and Solaris are detected. I'm not up to speed on autoconf/automake, so I did not implement that.