(Torturing the Scanner): Test the scanner on

an empty input file, which was Tim Van Holder's test case.

tests/input.at

@@ -92,6 +92,13 @@ AT_CLEANUP
 
 AT_SETUP([Torturing the Scanner])
 
+
+AT_DATA([input.y], [])
+AT_CHECK([bison input.y], [1], [],
+[[input.y:1.1: syntax error, unexpected "end of file"
+]])
+
+
 AT_DATA_GRAMMAR([input.y],
 [[%{
 /* This is seen in GCC: a %{ and %} in middle of a comment. */