autogen: Fix #2, add configure option for iniparser

Adds config option "--with-local-iniparser" [default=yes], which,
when set, will build using our built-in version of iniparser.

If explicitly unset, will perform a pkg-config check for iniparser,
which will fall back to our built-in version if not found.

Signed-off-by: Shane Bryan <shane.bryan@intel.com>