The path to the MoltenVK library can be specified by the
LIBMOLTENVK_PATH environment variable, otherwise it assumes it is
located in the application bundle's Contents/MacOS directory.
This replaces usages of the non-standard __FUNCTION__ macro with the standard
mandated __func__ identifier.
__FUNCTION__ is a preprocessor definition that is provided as an
extension by compilers. This was the only convenient option to rely on
pre-C++11. However, C++11 and greater mandate the predefined identifier
__func__, which lets us accomplish the same thing.
The difference between the two, however, is that __func__ isn't a
preprocessor macro, it's an actual identifier that exists at function
scope. The C++17 draft standard (N4659) at section [dcl.fct.def.general]
paragraph 8 states:
"
The function-local predefined variable __func__ is defined as if a
definition of the form
static const char __func__[] = "function-name ";
had been provided, where function-name is an implementation-defined
string. It is unspecified whether such
a variable has an address distinct from that of any other object in the
program.
"
Thankfully, we don't do any macro or string concatenation with __FUNCTION__
that can't be modified to use __func__.
