The script make-event-config.sed was mangling all the symbols by
prefixing them with "EVENT__". The problem here is that some
symbols aren't for local consumption within libevent, but rather
influence other system header files (ex: __USE_FILE_OFFSET64 is
used by dozens of header files including <sys/sendfile.h>).
As a workaround, all symbols starting with a capital letter only
(with the exception of STDC_HEADERS which must also be left
untouched) will be mangled.
Future contributors will need to be aware of this distinction.
This approach should make the creation of the file more atomic, to
fix a bug reported by Dinh.
This patch has one change from Zack's original version: it avoids
$<, since Dave Hart tells me he thinks that's not so portable.
(commit message by nickm)
