cblas_xerbla_internal.h collects the routine-name construction and the
row-major INFO remapping that the library and the test harness each
open-code today, so the two copies can no longer drift apart.
Relative to those copies the helper also trims the blank padding Fortran
supplies, drops the _64 suffix that BUILD_INDEX64_EXT_API rewrites into
the XERBLA name literals, matches operation names exactly rather than by
substring, and derives its buffer size from a named maximum so that long
names are clamped instead of silently truncated.
It has no user yet; the xerbla sources are switched over next.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
