Universal ctags also reports NEWLANG as the language for input.c.

================== THE ORIGINAL DOCUMENT ==================

Currently this test case made an assertion failure.
See also #402.

"OK.zzz ", a line of input.c changes the language, the value stored to
a global variable, File.source.language.

Initially ctags sets C to File.source.language.  However, ctags sets
NEWLANG to it as specified in args.ctags when ctags reads the line.

Reset the language is not so bad. However, when the preprocessor part(get.c)
of C parser reads "#define x 1" from input stream, get.c makes a
'v, variable definitions' kind tag. Such kind doesn't exist in the kind table of
NEWLANG. This makes the assertion failure.

We can remove the code which reset File.source.language to avoid the
assertion failure::

```
    diff --git a/main/read.c b/main/read.c
    index 91c661c..79af808 100644
    --- a/main/read.c
    +++ b/main/read.c
    @@ -118,7 +118,7 @@ static boolean setSourceFileName (vString *const fileName)
				    vStringValue (File.path), vStringValue (fileName));
			    pathName = vStringNewOwn (tmp);
		    }
    -		setSourceFileParameters (pathName, language);
    +		setSourceFileParameters (pathName, getSourceLanguage());
		    result = TRUE;
	    }
	    return result;
```

This looks good to me. However the output (tags file) becomes incompatible
to exuberant ctags when --fields=+l option is given to ctags.

```
[exuberant]$ ctags -o - --fields='+l' \
             --langdef=NEWLANG --langmap=NEWLANG:+.zzz --line-directives --excmd=number \
             Units/review-needed.r/line_directives.c.d/input.c
ctags: Warning: Ignoring non-option in ./.ctags

a	Units/review-needed.r/line_directives.c.d/a.c	10;"	v	language:C
b	Units/review-needed.r/line_directives.c.d/b.c	20;"	v	language:C
c	Units/review-needed.r/line_directives.c.d/c.c	30;"	v	language:C
d	Units/review-needed.r/line_directives.c.d/OK.zzz	2;"	v	language:NEWLANG

[universal]$ ./ctags -o - --fields='+l' \
             --langdef=NEWLANG --langmap=NEWLANG:+.zzz --line-directives --excmd=number \
             Units/review-needed.r/line_directives.c.d/input.c

a	Units/review-needed.r/line_directives.c.d/a.c	10;"	v	language:C
b	Units/review-needed.r/line_directives.c.d/b.c	20;"	v	language:C
c	Units/review-needed.r/line_directives.c.d/c.c	30;"	v	language:C
d	Units/review-needed.r/line_directives.c.d/OK.zzz	2;"	v	language:C
```

Exuberant ctags reports NEWLANG as the language of OK.zzz.
Universal ctags reports C as the language of OK.zzz.

'v' is a kind of C language. So even we ignore the assertion
issue, C should be reported. This is my position.

As suffix shows OK.zzz is obviously not a C language source
code. Reporting C as its language is wrong. This may be
the position of exuberant ctags.

I replaced expected.tags with the output of universal ctags
with the above patch.