Workaround for '__func__' undeclared compiler errors

Occasionally when compiling newer software on systems with older compilers such as Red Hat 6.2's egcs-1.1.2 (gcc-2.91), you may get an error such as:

`__func__' undeclared (first use in this function)

This can usually be worked around by adding the following to the top of the particular file that gave the error.

#define __func__ __FUNCTION__

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