This adds an alternative to using #... in dump files, useful where we
only want to allow specific extra output. DW_CFA_nop in CIEs and FDEs
to pad out to required alignment (larger for 64-bit than 32-bit) is
an example where these optional match patterns are useful.
binutils/
* testsuite/lib/binutils-common.exp (regexp_diff): Support #?REGEXP.
ld/
* testsuite/ld-elf/eh4.d: Match optional padding DW_CFA_nop in FDEs.
* testsuite/ld-elf/eh5.d: Likewise, and extra CIEs emitted on
embedded targets.
bc754168c7