gnutls_memset: use explicit_bzero
That is, use the glibc function when available and the second parameter is zero.
Checklist
-
Code modified for feature -
Test suite updated with functionality tests
Reviewer's checklist:
-
Any issues marked for closing are addressed -
There is a test suite reasonably covering new functionality or modifications -
Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTION.md
-
This feature/change has adequate documentation added -
No obvious mistakes in the code