[Bug libstdc++/60401] stdlib.h does not provide abs(long) overload

[vogt at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60401

--- Comment #7 from Dominik Vogt <vogt at linux dot vnet.ibm.com> ---
Created attachment 37408
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37408&action=edit
List of errors

This is a list of all remaining errors of the Plumhall test.  I've not checked
whether they all depend on math.h.