Issue 50580 - Perl can't be disabled in configure
Due to incorrect use of AC_ARG_ENABLE macro arguments' semantics some
calls like ./configure --disable-* and --enable-*=no worked
unexpectedly like --enable-*=yes.
As this issue affects several ./configure options all were fixed. The
fix uses the fourth argument of the AC_ARG_ENABLE to set the default in
case no option was provided. In case an explicit --disable-* or
--enable-* argument was provided to ./configure the respective $enable_*
variable is implicitly populated by autoconf, hence subsequent
if-else statements take care of additional operations based on the
For the record, some implementations of the options pre-set the default
value before the AC_ARG_ENABLE in case the respective $enable_* variable
has not been set. This is a correct approach, hence left as is.
Author: Matus Honek <email@example.com>
Review-By: Mark (thanks!)