Fixes in configure.ac

* am/enable.m4 (MU_ENABLE_SUPPORT): Change semantics of the
last argument.
(MU_ENABLE_BUILD): 4th argument gives additional conditions for
AM_CONDITIONAL.
* configure.ac: Enable building c++ interface when possible.
Fix checks for guimb and mh utilities.
* libmu_cpp/Makefile.am: Remove unnecessary substitution
variables.

 dnl This file is part of GNU mailutils.
-dnl Copyright (C) 2002, 2005, 2007 Free Software Foundation, Inc.
+dnl Copyright (C) 2002, 2005, 2007, 2009 Free Software Foundation, Inc.
 dnl
 dnl This program is free software; you can redistribute it and/or modify
 dnl it under the terms of the GNU General Public License as published by
@@ -17,7 +17,7 @@ dnl Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 dnl
 
 dnl MU_ENABLE_SUPPORT(feature, [action-if-true], [action-if-false],
-dnl                   [action-default])
+dnl                   [default-value])
 
 AC_DEFUN([MU_ENABLE_SUPPORT], [
 	pushdef([mu_upcase],translit($1,[a-z+-],[A-ZX_]))
@@ -32,7 +32,7 @@ AC_DEFUN([MU_ENABLE_SUPPORT], [
                 no)  mu_cache_var=no;;
 	        *)   AC_MSG_ERROR([bad value ${enableval} for --disable-$1]) ;;
         esac],
-                      [ifelse([$4],,mu_cache_var=yes,[$4])])
+                      [mu_cache_var=ifelse([$4],,yes,[$4])])
 
 	if test x"[$]mu_cache_var" = x"yes"; then
 		ifelse([$2],,:,[$2])
@@ -46,6 +46,8 @@ AC_DEFUN([MU_ENABLE_SUPPORT], [
 	popdef([mu_cache_var])
 ])
 
+dnl MU_ENABLE_BUILD(feature, [action-if-true], [action-if-false],
+dnl                 [additional-cond], [default-value])
 AC_DEFUN([MU_ENABLE_BUILD], [
 	pushdef([mu_upcase],translit($1,[a-z+-],[A-ZX_]))
 	pushdef([mu_cache_var],[mu_cv_enable_build_]translit($1,[+-],[x_]))
@@ -60,18 +62,18 @@ AC_DEFUN([MU_ENABLE_BUILD], [
                 no)  mu_cache_var=no;;
 	        *)   AC_MSG_ERROR([bad value ${enableval} for --disable-$1]) ;;
         esac],
-                      [ifelse([$4],,mu_cache_var=yes,[$4])])
+                      [mu_cache_var=ifelse([$5],,yes,[$5])])
 
 	if test x"[$]mu_cache_var" = x"yes"; then
 		ifelse([$2],,:,[$2])
 	ifelse([$3],,,else
                [$3])
 	fi
-	if test x"[$]mu_cache_var" = x"yes"; then
+	if test x"[$]mu_cache_var" = x"yes" ifelse($4,,,[&& $4]); then
 		AC_DEFINE([MU_BUILD_]mu_upcase,1,[Define this if you build $1])
         fi
 	AM_CONDITIONAL(mu_cond,
-	               [test x"[$]mu_cache_var" = x"yes"])
+	               [test x"[$]mu_cache_var" = x"yes" ifelse($4,,,[&& $4])])
 	
 	popdef([mu_upcase])
 	popdef([mu_cache_var])

@@ -1142,10 +1142,7 @@ AM_CONDITIONAL([MU_COND_PYTHON], [test "$status_python" = yes])
 AC_SUBST(MU_CXX_LTLIBRARIES_BUILD)
 AC_SUBST(MU_CXX_EXAMPLES_BUILD)
 MU_ENABLE_SUPPORT(c++,
-  	          [MU_CXX_LTLIBRARIES_BUILD='$(MU_CXX_LTLIBRARIES_LIST)'
-	           MU_CXX_EXAMPLES_BUILD='$(MU_CXX_EXAMPLES_LIST)'],
-		  :,
-		  [mu_cv_enable_cxx=$mu_build_experimental])
+  	          [MU_CXX_EXAMPLES_BUILD='$(MU_CXX_EXAMPLES_LIST)'])
 
 # Default mailbox record
 # Note: 1. Support for mbox type is always enabled.
@@ -1189,18 +1186,14 @@ MU_ENABLE_BUILD(comsat)
 MU_ENABLE_BUILD(maidag)
 MU_ENABLE_BUILD(mail)
 MU_ENABLE_BUILD(sieve)
-if test "$useguile" = yes; then
-  MU_ENABLE_BUILD(guimb)
-fi
+MU_ENABLE_BUILD(guimb,,,[test "$useguile" = yes])
 MU_ENABLE_BUILD(messages)
 MU_ENABLE_BUILD(readmsg)
 MU_ENABLE_BUILD(dotlock)
 MU_ENABLE_BUILD(movemail)
 MU_ENABLE_BUILD(mimeview)
 
-if test "$mu_cv_enable_mh" = yes; then
-  MU_ENABLE_BUILD(mh)
-fi
+MU_ENABLE_BUILD(mh,,,[test "$mu_cv_enable_mh" = yes])
 
 AC_SUBST(MH_BIN_DIR)
 

@@ -19,9 +19,7 @@
 
 INCLUDES = @MU_LIB_COMMON_INCLUDES@ 
 
-MU_CXX_LTLIBRARIES_LIST = libmu_cpp.la
-lib_LTLIBRARIES = @MU_CXX_LTLIBRARIES_BUILD@
-EXTRA_LTLIBRARIES = $(MU_CXX_LTLIBRARIES_LIST)
+lib_LTLIBRARIES = libmu_cpp.la
 
 libmu_cpp_la_SOURCES = \
  address.cc\