When reporting an error for a construct which hasn't been terminated

when the end of the file is reached, report it at the start line rather
than "EOF" as then tools like editors and IDEs will take you to a
generally more useful place for fixing the problem.

Examples/test-suite/errors/pp_missing_enddef.stderr

@@ -1 +1 @@
-pp_missing_enddef.i:EOF: Error: Missing %enddef for macro starting on line 3
+pp_missing_enddef.i:3: Error: Missing %enddef for macro starting here

Examples/test-suite/errors/pp_missing_endif.stderr

@@ -1 +1 @@
-pp_missing_endif.i:EOF: Error: Missing #endif for conditional starting on line 3
+pp_missing_endif.i:3: Error: Missing #endif for conditional starting here

Examples/test-suite/errors/pp_missing_endoffile.i

@@ -0,0 +1,7 @@
+%module xxx
+/* %beginfile and %endoffile are internal directives inserted when %include is
+ * used.  Users should never use them directly, but test coverage for this
+ * error message still seems useful to have.
+ */
+%includefile "dummy.i" %beginfile
+

Examples/test-suite/errors/pp_missing_endoffile.stderr

@@ -0,0 +1 @@
+pp_missing_endoffile.i:6: Error: Missing %endoffile for file inclusion block starting here

Examples/test-suite/errors/pp_missing_rblock.stderr

@@ -1 +1 @@
-pp_missing_rblock.i:EOF: Error: Unterminated %{ ... %} block starting on line 3
+pp_missing_rblock.i:3: Error: Unterminated %{ ... %} block

Examples/test-suite/errors/pp_unterm_char.stderr

@@ -1 +1 @@
-pp_unterm_char.i:EOF: Error: Unterminated character constant starting at line 4
+pp_unterm_char.i:4: Error: Unterminated character constant

Examples/test-suite/errors/pp_unterm_comment.stderr

@@ -1 +1 @@
-pp_unterm_comment.i:EOF: Error: Unterminated comment starting on line 3
+pp_unterm_comment.i:3: Error: Unterminated comment

Examples/test-suite/errors/pp_unterm_string.stderr

@@ -1 +1 @@
-pp_unterm_string.i:EOF: Error: Unterminated string constant starting at line 4
+pp_unterm_string.i:4: Error: Unterminated string constant