Enable utils.

  I removed the --disable-utils switch to see if that fixes the Ruby 2.0/Centos 6.4 issue.
Remove env call.

  This was causing the build to fail with this message:
    relocation R_X86_64_32 against `.rodata.str1.1' can not be used when making a shared object; recompile with -fPIC
Moved -fPIC compiler flag to CXXFLAGS.
Removed --disable-shared flag.
Also build static library.
Try setting envars properly.
Another pass at envars.

  This partially reverts 37b1291fcf4f4180c66285941f591f6d65f55df9
  It looks like ruby globals $<var> are used by mkmf.rb (cf create_makefile)
Upgrade to libmemcache-1.0.6.
Merge pull request #16 from ss/master

Ruby 2.0 fixes.