Comment 15 for bug 180179

We have several options.

1. Change the implementation of the GCC -Wstrict-prototypes
to only warn about actual invocation of a function declared
without specifying the argument types. That is, the mere
declaration of a function without specifying the argument
types should not cause a warning. Only the act of calling
such a function should be warned.

This is to recognize the existence of code that defines a
generic function pointer type like this:

  typedef int (*func_ptr_t)();

or this:

  typedef void (*func_ptr_t)();

2. Do not use -Wstrict-prototypes on files that include "prlink.h".

3. Ignore the -Wstrict-prototypes warnings in "prlink.h".

4. Change "prlink.h" to suppress this warning. I think

#pragma GCC diagnostic ignored "-Wstrict-prototypes"

should work. But I don't know how to make it apply to
only certain lines in "prlink.h", and restore to the *original
setting*.

5. Change the definition of PRFuncPtr in "prlink.h". As
I explained before, NSPR needs to be backward compatible
(at both source and binary levels), which means existing
code should continue to compile against new versions of
NSPR headers. This is why I have to perform a lot of
experiments (GCC, Visual C++, Sun Studio, HP C, and IBM
C compilers) to see if changing the definition of
PRFuncPtr breaks the compilation or generates compiler
warnings on the sample code I gave in comment 6.