Change PAPI_ENUM_ALL to PAPI_ENUM_EVENTS.  Seems the _ALL constant is not always defined, and this was breaking the build on nigel.
Change PAPI_ENUM_ALL to PAPI_ENUM_EVENTS.  Seems the _ALL constant
is not always defined, and this was breaking the build on nigel.

zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit,zcth428/hpctoolkit,zcth428/hpctoolkit111,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,zcth428/hpctoolkit,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit111,HPCToolkit/hpctoolkit,zcth428/hpctoolkit