[evolution] Remove --enable-plugins=list variation.

[Matthew Barnes <mbarnes src gnome org>]

commit 0fdd38639fa1734b5fff24d9dbd34bb9e1492742
Author: Matthew Barnes <mbarnes redhat com>
Date:   Mon Jun 18 20:57:25 2012 -0400

    Remove --enable-plugins=list variation.
    
    With the removal of the 'experimental' plugin group, passing
    --enable-plugins=experimental to configure will now cause the Makefile
    to try and build a plugin named 'experimental', which will result in a
    mysterious "experimental: No such file or directory" build error.
    
    This is because of the "list" fallback behavior: if the option is not
    one of "no", "base" or "all" then the configure script assumes it to be
    a list of plugin names.  I've never known that to be useful to anyone,
    so remove the "list of plugin names" behavior and replace it with an
    informative error message.
    
    Eventually the --enable-plugins will be removed entirely since EPlugin
    is deprecated.

 configure.ac |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 911a224..475c4ac 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1224,7 +1224,7 @@ EVO_PLUGIN_RULE=$srcdir/plugin.mk
 AC_SUBST_FILE(EVO_PLUGIN_RULE)
 
 AC_ARG_ENABLE([plugins],
-	AS_HELP_STRING([--enable-plugins=[no/base/all/list]],
+	AS_HELP_STRING([--enable-plugins=[no/base/all]],
 	[Enable plugins.]),
 	[enable_plugins="$enableval"],[enable_plugins=all])
 
@@ -1383,8 +1383,8 @@ xbase)
 	msg_plugins="yes ($plugins_base)"
 	;;
 *)
-	plugins_enabled="$enable_plugins"
-	msg_plugins="yes ($enable_plugins)"
+	AC_MSG_ERROR([Invalid value for --enable-plugins.
+	Please specify either "no", "base", or "all" (default=all)])
 	;;
 esac