This commit removes the previous tdesc_cortex_a, tdesc_cortex_m, and
tdesc_cortex_mf XML string literals used for target description to GDB,
now instead programmatically generating them at runtime to significantly
deduplicate the characters that get embedded into the binary.
Output of ld's --print-memory-usage during final link before:
Memory region Used Size Region Size %age Used
rom: 116388 B 128 KB 88.80%
ram: 3348 B 20 KB 16.35%
Output of ld's --print-memory-usage during final link now:
Memory region Used Size Region Size %age Used
rom: 113032 B 128 KB 86.24%
ram: 3376 B 20 KB 16.48%
So all in all this saves 3356 bytes of flash.
Note: the exact size saved when compiled on your machine may differ, as
the size of the build seems at least partially non-deterministic.
We've gotten slightly different sizes (within 15 bytes of each other)
at different times, with the only differences being things like which
files were rebuilt in an incremental rebuild, or the order object files
were given to the linker command line. The numbers given above were the
numbers we got when testing the final builds from scratch, but all the
sizes we got were extremely similar to the sizes listed above.
c136b919cd