implicitaimplicit declaration of function 'setup_log_handler'

[Ryan Schmidt]

Building utimer 0.4 fails with Xcode 12's version of clang on macOS 10.15 or later with:

maintests.c:232:3: error: implicit declaration of function 'setup_log_handler' is invalid in C99 [-Werror,-Wimplicit-function-declaration]

Implicit declaration of function used to be a warning but as of Xcode 12 it is an error.

This was reported to MacPorts here:

https://trac.macports.org/ticket/61582

[Ryan Schmidt (z-launchpad-d)]

Here is the patch I committed to MacPorts to fix this.

The setup_log_handler function had been declared without a parameter list so I fixed that as well by making it void. There are several other functions in your codebase without parameter lists that should be fixed too.