if people wonder where this comes from:
the BUG_ON code sequence is 13 bytes, the WARN_ON sequence
is 24 bytes, so 11 bytes longer. HOWEVER, the BUG_ON approach
also needs 12 bytes of data (20 on 64 bit) per bug, a nett loss
of 1 byte on 32 bit x86. (plus some general overhead for storing
sections as such, but that scales per ELF file, not per BUG_ON instance)
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