Refactoring the GCC cross compilers

Kia ora koutou,
We've been creating new GCC targets in pkgsrc/cross by simply copying 
the Makefiles for other targets and the amount of duplication has got 
out of hand. We have five U-Boot architectures that use these cross 
compilers and the U-Boot docs make it quite clear that they do not 
expect us to maintain GCC 8 from 2018.

We've also got a large number of patches that are simply not needed any 
more because upstream has applied the patch and we simply haven't 
updated our end to use the updated toolchain.

The only difference between these packages is the GNU target triple and 
sometimes the GCC version.

I have created in WIP a directory called common-gnu-toolchain that 
contains the common Makefile fragments, distinfo files and patches. I 
have also created in WIP the following packages to use this refactored code.

* aarch64-none-elf-binutils
* aarch64-none-elf-gcc

* arm-none-eabi-binutils
* arm-none-eabi-gcc
* arm-none-eabi-gdb

* mipsel-none-elf-binutils
* mipsel-none-elf-gcc

* powerpc-none-elf-binutils
* powerpc-none-elf-gcc

* riscv64-none-elf-binutils
* riscv64-none-elf-gcc
* riscv64-none-elf-gdb

The package Makefiles are now pretty much just

     TARGET=        arm-none-eabi
     MAINTAINER=    [email protected]
     COMMENT=    Cross binutils for bare metal ARM EABI

     .include "../../wip/common-gnu-toolchain/binutils.mk"
     .include "../../mk/bsd.pkg.mk"

Most GCCs have been upgraded to 14.3, but powerpc and mipsel cross 
compilers are still using GCC 13.2 because newlib for those platforms 
has K&R code for testing the linker and it won't compile with a newer 
GCC. Upstream is working on that problem.

I'm currently working though the pkglint reports for each package.

I have removed the TEXINFO_REQD for gcc because it doesn't seem to be 
required on NetBSD 11 and I expect that it will need to be turned back 
on for older versions of NetBSD.

I have put this all in pkgsrc WIP because I'm hoping it will be easier 
to see what I've done there rather than trying to read diffs covering a 
dozen directories.

I would like feedback and approval before commiting this to pkgsrc itself.

Ngā mihi,
Lloyd