Have utilities ignore case in event names.

[Vince Weaver]

From Steve Kaufman on 24 July 2017:

It might be nice to allow utilities such as papi_native_avail to ignore case when identifying event names. When papi_native_avails' -i or -x option is used the case of the string should be ignored. This involves changing the 'strstr' calls in the code to 'strcasestr'. This logic could be extended to any other utilities that perform event name selection via a string. I believe event names processed in PAPI/libpfm4 are done regardless of case anyways(?).