(byte-compile-warning-prefix):

(byte-compile-warning-prefix):
Decide here whether to print which form we're compiling.
If we do that, still print file and line.  Make file name
relative to default-directory.	Print fewer newlines.
(byte-compile-log-file): Print something even if no file.
Print messages for entering and leaving directories,
and set default-directory.
(displaying-byte-compile-warnings): Only sometimes bind warning-series.
(byte-compile-warning-series): New function.
(byte-compile-file): Set byte-compile-last-logged-file, don't bind it.
(byte-compile-display-log-head-p): Function deleted.