* automake.in (lang_yacc_target_hook): Add rule to recover from the removal of $header. * lib/am/yacc.am (%BASE%.h): Remove (duplicate with the one output by lang_yacc_target_hook). * tests/yacc7.test: Try to recreate foo.h after its removal. * tests/yacc8.test: Add `AM_YFLAGS = -d' and try to recreate parse.h too. Reported by Bernd Jendrissek.