Merge branch 'yacc-work' into maint

* yacc-work:
  news: update about recent ylwrap changes and fixes
  yacc tests: fix a spurious failure with parallel make
  ylwrap: use proper quoting inside a `...` substitution
  ylwrap: don't uselessly reset the exit status in case of failure
  ylwrap: fix C++ support for Bison
  ylwrap: refactor: move loop invariant
  ylwrap: refactoring: don't rely on the file order
  tests: upgrade and fix Bison test case
  tests: fix bison input file
  ylwrap: comment changes
  ylwrap: modernize idioms
  ylwrap: rename header inclusion in generated parsers
  ylwrap: simplify the list of renamings
  ylwrap: refactor: less duplication

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

diff --cc NEWS
index 77344f8,0831852..f468570
--- 1/NEWS
--- 2/NEWS
+++ b/NEWS
@@@ -66,16 -66,22 +66,28 @@@ New in 1.12.3
      giving more useful warnings than a bare "command not found" from a
      make recipe would.
  
 -* Automake Testsuite:
 -
 -  - Some testsuite weaknesses and spurious failures have been fixed.
 -
 +* M4 files:
 +
 +  - The '.m4' files provided by Automake does not define serial numbers
 +    anymore.  This should cause no difference in the behaviour of aclocal
 +    though.
 +
 +* Automake Testsuite:
 +
 +  - Some testsuite weaknesses and spurious failures have been fixed.
 +
+ * Long-standing bugs:
+ 
+   - Instead of renaming only self-references of files (typically for
+     #lines), ylwrap now also renames references to the other generated
+     files.  This fixes support for GLR and C++ parsers from Bison (PR
+     automake/491 and automake bug#7648): 'parser.c' now properly
+     #includes 'parser.h' instead of 'y.tab.h'.
+ 
+   - Generated files unknown to ylwrap are now preserved.  This fixes
+     C++ support for Bison (automake bug#7648): location.hh and the
+     like are no longer discarded.
+ 
  New in 1.12.2:
  
  * Warnings and deprecations: