Clean up and comment the use of local for static.

adler32.c

@@ -7,8 +7,6 @@
 
 #include "zutil.h"
 
-#define local static
-
 local uLong adler32_combine_ OF((uLong adler1, uLong adler2, z_off64_t len2));
 
 #define BASE 65521U     /* largest prime smaller than 65536 */

crc32.c

@@ -30,8 +30,6 @@
 
 #include "zutil.h"      /* for STDC and FAR definitions */
 
-#define local static
-
 /* Definitions for doing the crc four data bytes at a time. */
 #if !defined(NOBYFOUR) && defined(Z_U4)
 #  define BYFOUR

gzguts.h

@@ -114,7 +114,9 @@
 #ifndef local
 #  define local static
 #endif
-/* compile with -Dlocal if your debugger can't find static symbols */
+/* since "static" is used to mean two completely different things in C, we
+   define "local" for the non-static meaning of "static", for readability
+   (compile with -Dlocal if your debugger can't find static symbols) */
 
 /* gz* functions always use library allocation functions */
 #ifndef STDC

zutil.h

@@ -36,7 +36,9 @@
 #ifndef local
 #  define local static
 #endif
-/* compile with -Dlocal if your debugger can't find static symbols */
+/* since "static" is used to mean two completely different things in C, we
+   define "local" for the non-static meaning of "static", for readability
+   (compile with -Dlocal if your debugger can't find static symbols) */
 
 typedef unsigned char  uch;
 typedef uch FAR uchf;