Add CPU execution trace - #3

…race

…a file instead

In older GCC version, .option arch, -c worked but now it is not
Using .option norvc even though it is deprecated now

new GCC emits defines based on -mstrict-align which might be
respected in some code (namely preprocessed assembly like newlib)

this fact was find by 'dmem_haddr_align' assertion

Fix JALR target LSB to be zero

Enum without any type is consider as 'int' with whatever it comes
with (e.g., no Xs)

Obsevation: 1-bit enums are not labeled when using FST generated
by Verilator and displayed in GTKWave... most likely a bug

without this check, verilator prints its error message which
might suggest user to use another unvalid values for X_VAL

previously, it was possible using +verilator+rand+reset argument
it was working in version 5.020 but not in 5.032