cfitsio 3.31 patches

A patch that upgrades cfitsio 3.31 is available under
my home directory www.mpia.de/~mathar/progs/cfitsio.patch
in diff format:

- Variables that were declared or initialized but not used have been removed.

- Some comments have been closed by */

- Some long long integer formatting has been changed from %ld to %lld

- Static functions that were not used have been removed.

- K&R style of argument declarations have been upgraded to ANSI-C style.

- Most importantly, const declarations have been added where possible.
This avoids that one needs to work around stricter usage checks
in modern compilers. This is an ongoing project.