build: fix support for --disable-dependency-tracking

Reported by Juan Manuel Guerrero.
https://lists.gnu.org/archive/html/bug-bison/2014-07/msg00000.html.

* examples/local.mk (%D%/extracted.stamp): Make sure the output
directory exists.
* examples/extexi (process): Likewise.

examples/extexi

@@ -47,6 +47,9 @@
 
 use strict;
 
+use File::Basename qw(dirname);
+use File::Path qw(make_path);
+
 # Whether we generate synclines.
 my $synclines = 0;
 
@@ -92,7 +95,9 @@ sub file_wanted ($)
   undef
 }
 
-
+# process ($in)
+# -------------
+# Read input file $in, and generate the outputs.
 sub process ($)
 {
   my ($in) = @_;
@@ -152,7 +157,7 @@ sub process ($)
   # Output the files.
   for my $file (keys %file)
     {
-      # No spurious end of line: use printf.
+      make_path (dirname ($file));
       my $o = new IO::File(">$file")
         or die "$file: cannot create: $?";
       print $o $file{$file}{$_}

examples/local.mk

@@ -33,6 +33,7 @@ extracted =
 CLEANFILES += $(extracted) %D%/extracted.stamp
 %D%/extracted.stamp: $(doc) $(extexi)
 	$(AM_V_GEN)rm -f $@ $@.tmp
+	$(AM_V_at)$(MKDIR_P) %D%
 	$(AM_V_at)touch $@.tmp
 	$(AM_V_at)$(extract) $(extracted)
 	$(AM_V_at)mv $@.tmp $@