Add support for LoongArch.

[liuxiang88]

The LoongArch architecture (LoongArch) is an Instruction Set Architecture (ISA) that has a RISC style.

Documentations:
ISA:
https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html
ABI:
https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html
More docs can be found at:
https://loongson.github.io/LoongArch-Documentation/README-EN.html

[olebole]

Thank you for this patch! I am happy to see this port!
I have just two remarks: First, the change in cfitsio.h is almost obsolete, as we are going to remove cfitsio from IRAF (#330 is ready for merge, just kept open for discussion with NOIRLAB).
And could you add the CPU type to INSTALL.md as well?

[olebole]

An attempt to build IRAF on LoongArch failed on Debian:

cc -Wdate-time -D_FORTIFY_SOURCE=2 -g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -I/<<PKGBUILDDIR>>/unix/hlib/libc -D_GNU_SOURCE -DNOVOS -Wdate-time -D_FORTIFY_SOURCE=2  -c -o zgmtco.o zgmtco.c
In file included from /usr/include/linux/stat.h:5,
                 from /usr/include/loongarch64-linux-gnu/bits/statx.h:31,
                 from /usr/include/loongarch64-linux-gnu/sys/stat.h:465,
                 from zfiond.c:5:
/usr/include/linux/types.h:5:10: fatal error: asm/types.h: No such file or directory
    5 | #include <asm/types.h>
      |          ^~~~~~~~~~~~~
compilation terminated.
make[4]: *** [<builtin>: zfiond.o] Error 1
make[4]: *** Waiting for unfinished jobs....
make[4]: *** [<builtin>: zfmkdr.o] Error 1
In file included from /usr/include/signal.h:301,
                 from zpanic.c:5:
/usr/include/loongarch64-linux-gnu/bits/sigcontext.h:30:11: fatal error: asm/sigcontext.h: No such file or directory
   30 | # include <asm/sigcontext.h>
      |           ^~~~~~~~~~~~~~~~~~
compilation terminated.
[…]

Full build log here.
Could you fix this?

[olebole]

The change in cfitsio should be omitted here, since we are going to remove cfitsio soon.

[liuxiang88]

I just spent some time to confirm that this error is because the current version of linux-libc-dev on the buildd has not yet been merged into the patch to fix this problem.It can be resolved with a lower version of the kernel, 6.6.9-1+loong64 for now.

[olebole]

Because I have no access to a loonghorn machine, I would wait until we see a successful build on Debian. Alternatively, could you attach a build and test log from a build if you tested it?

[liuxiang88]

I see.Here is my local build log.

complete-debian-build-iraf.log
test-result.log

[olebole]

Thank you very much! I will merge it once I finished with the NOIRLAB changes.

[liuxiang88]

OK,thank you very mach!