InlineX::C2XS - create an XS file from an Inline C file.

The C file that InlineX::C2XS needs to find would contain
only the C code.

InlineX::C2XS looks for the file in ./src directory,
expecting that the filename will be the same as what
appears after the final '::' in the module name (with a
'.c' extension).ie if the module is calle My::Next::Mod
it looks for a file ./src/Mod.c, and creates a file
named Mod.xs. Also created, is the file 'INLINE.h' - but
only if that file is needed. The generated xs file (and
INLINE.h) will be written to the cwd unless a third argument
(specifying a valid directory) is provided to the c2xs()
function.

The created XS file, when packaged with the '.pm' file, an
appropriate 'Makefile.PL', and 'INLINE.h' (if it's needed),
can be used to build the module in the usual way - without
any dependence upon the Inline::C module
