minor awk cleanup diff

[Antti Nykänen <aon_(_at_)_iki_(_dot_)_fi>]

Hello,

Here are some small cleanups for awk.

Index: lex.c
===================================================================
RCS file: /cvs/src/usr.bin/awk/lex.c,v
retrieving revision 1.8
diff -r1.8 lex.c
371c371,372
< 	int c, n;
---
> 	int c;
> 	unsigned int n;
Index: lib.c
===================================================================
RCS file: /cvs/src/usr.bin/awk/lib.c,v
retrieving revision 1.16
diff -r1.16 lib.c
33a34
> #include <math.h>
614c615
< void error()
---
> void error(void)
714d714
< #include <math.h>