Note about the -tcc file:
HAVE_FLOAT_ASM defines if there's assembly support for float
instructions.
HAVE_FLOAT defines if there's floating point arithmetic support.
This is important for TinyCC because the assembler and the C
compiler are split. TinyCC can HAVE_FLOAT but no assembler support
for them.
* lib/riscv64-mes-gcc/setjmp.c,
lib/riscv64-mes-tcc/setjmp.c: New files.
* lib/riscv64-mes-gcc/setjmp.c: New file.
(setjmp, longjmp): Add dummy implementations. Implementing these for gcc
would be very involved, and does not seem necessary to get mescc to
work.