--- /dev/null
+--- a/lib/Automake/Variable.pm
++++ b/lib/Automake/Variable.pm
+@@ -1259,8 +1259,15 @@ sub output_variables ()
+ foreach my $var (@vars)
+ {
+ my $v = rvar $var;
++ # Output unconditional definitions before conditional ones.
++ if ($v->def (TRUE)) {
++ $res .= $v->output (TRUE)
++ if $v->rdef (TRUE)->owner == VAR_AUTOMAKE;
++ }
+ foreach my $cond ($v->conditions->conds)
+ {
++ # TRUE is handled already.
++ next if $cond->string eq "TRUE";
+ $res .= $v->output ($cond)
+ if $v->rdef ($cond)->owner == VAR_AUTOMAKE;
+ }
+@@ -1270,8 +1277,15 @@ sub output_variables ()
+ foreach my $var (@vars)
+ {
+ my $v = rvar $var;
++ # Output unconditional definitions before conditional ones.
++ if ($v->def (TRUE)) {
++ $res .= $v->output (TRUE)
++ if $v->rdef (TRUE)->owner != VAR_AUTOMAKE;
++ }
+ foreach my $cond ($v->conditions->conds)
+ {
++ # TRUE is handled already.
++ next if $cond->string eq "TRUE";
+ $res .= $v->output ($cond)
+ if $v->rdef ($cond)->owner != VAR_AUTOMAKE;
+ }
--- /dev/null
+--- a/bin/automake.in
++++ b/bin/automake.in
+@@ -4745,12 +4745,42 @@ sub handle_clean
+ if var ('CLEANFILES');
+ $clean_files{'$(DISTCLEANFILES)'} = DIST_CLEAN
+ if var ('DISTCLEANFILES');
+- $clean_files{'$(MAINTAINERCLEANFILES)'} = MAINTAINER_CLEAN
+- if var ('MAINTAINERCLEANFILES');
+
+ # Built sources are automatically removed by maintainer-clean.
+- $clean_files{'$(BUILT_SOURCES)'} = MAINTAINER_CLEAN
+- if var ('BUILT_SOURCES');
++ # For each defined condition of the maintainer-clean variable, append built sources
++ # and create an unconditional definition with built sources if not already defined.
++ # Then, for each definition of built sources without maintainer-clean defined, define it.
++ # Otherwise, if the variable is not user-defined, define it with built sources.
++ my $mcleanvar = var ('MAINTAINERCLEANFILES');
++ if ($mcleanvar) {
++ foreach my $rcond ($mcleanvar->conditions->conds)
++ {
++ if (! grep { $_ eq '$(BUILT_SOURCES)' } $mcleanvar->value_as_list ($rcond)) {
++ Automake::Variable::define ($mcleanvar->name, VAR_MAKEFILE, '+', $rcond,
++ '$(BUILT_SOURCES)', '', INTERNAL, VAR_ASIS)
++ if vardef ('BUILT_SOURCES', $rcond);
++ }
++ }
++ my $bsources = var ('BUILT_SOURCES');
++ if ($bsources) {
++ foreach my $rcond ($bsources->conditions->conds)
++ {
++ Automake::Variable::define ($mcleanvar->name, VAR_MAKEFILE, '', $rcond,
++ '$(BUILT_SOURCES)', '', INTERNAL, VAR_ASIS)
++ if ! vardef ($mcleanvar, $rcond);
++ }
++ if (! vardef ($mcleanvar, TRUE)) {
++ Automake::Variable::define ($mcleanvar->name, VAR_MAKEFILE, '', TRUE,
++ '$(BUILT_SOURCES)', '', INTERNAL, VAR_ASIS);
++ }
++ }
++ } else {
++ Automake::Variable::define ('MAINTAINERCLEANFILES', VAR_MAKEFILE, '', TRUE,
++ '$(BUILT_SOURCES)', '', INTERNAL, VAR_ASIS)
++ if var ('BUILT_SOURCES');
++ }
++ $clean_files{'$(MAINTAINERCLEANFILES)'} = MAINTAINER_CLEAN
++ if var ('MAINTAINERCLEANFILES');
+
+ # Compute a list of "rm"s to run for each target.
+ my %rms = (MOSTLY_CLEAN, [],