gdbarch.sh generates wrong #line markers

[cooljeanius]

The gdbarch.sh script sometimes generates incorrect #line markers when creating gdbarch.c and gdbarch.h, which can cause diagnostics for those files to be confusing. (This is related to bug #1, for reference.)

(Note: I formerly had a bounty for this on BountySource, but then I deleted my BountySource account due to bad interactions with them on social media, so now if you are interested in a bounty, contact me separately to find a way to do it outside of their system)

[cooljeanius]

Semi-related: now that I've added line markers to the cgen scheme used to generate certain opcodes sources, the line numbers there don't seem to work, either...