examples: add empty lines

[Akim Demaille]

That was badly needed to make the files nicer to read.  Will be pushed in 
master.

commit 32e0fd1a99308d5311ec8508b558cb2401863d23
Author: Akim Demaille <address@hidden>
Date:   Sun Aug 19 17:34:27 2018 +0200

    examples: add empty lines
    
    Currently the examples are too dense, let's put empty lines where
    '#line' would be issued.  And also remove some spurious empty
    lines (remains from @group, @end group, etc.).
    
    * examples/extexi: Do that.
    * examples/local.mk (extexiFLAGS): Rename as...
    (EXTEXIFLAGS): this.

diff --git a/examples/extexi b/examples/extexi
index 40d16e38..95c6c395 100755
--- a/examples/extexi
+++ b/examples/extexi
@@ -45,7 +45,7 @@ sub normalize($)
 {
   local ($_) = @_;
 
-  s/^\@(c |comment|dots|end (ignore|group)|ignore|group).*//mg;
+  s/^\@(c |comment|dots|end (ignore|group)|ignore|group).*\n//mg;
   s/address@hidden/$ENV{VERSION}/g;
   s/^\@(error|result)\{\}//mg;
   s/\@(address@hidden)/$1/g;
@@ -103,6 +103,7 @@ sub process ($)
         {
           if (/^\@(small)?example$/)
             {
+              $input .= "\n" unless defined $input;
               # Bison supports synclines, but not Flex.
               $input .= sprintf ("#line %s \"$in\"\n", $. + 1)
                 if $synclines && $file =~ /\.[chy]*$/;
diff --git a/examples/local.mk b/examples/local.mk
index 13f8d492..2518da34 100644
--- a/examples/local.mk
+++ b/examples/local.mk
@@ -26,9 +26,9 @@ AM_CXXFLAGS =                                                 
\
 doc = $(top_srcdir)/doc/bison.texi
 extexi = $(top_srcdir)/%D%/extexi
 if ENABLE_GCC_WARNINGS
-extexiFLAGS = --synclines
+EXTEXIFLAGS = --synclines
 endif
-extract = VERSION="$(VERSION)" $(PERL) $(extexi) $(extexiFLAGS) $(doc) --
+extract = VERSION="$(VERSION)" $(PERL) $(extexi) $(EXTEXIFLAGS) $(doc) --
 extracted =
 CLEANFILES += $(extracted) %D%/extracted.stamp
 %D%/extracted.stamp: $(doc) $(extexi)