use "glibc errno" trick not only for ash, but for entire busybox

(add/remove: 1/1 grow/shrink: 37/37 up/down: 139/-228)        Total: -89 bytes

shell/ash.c

@@ -127,13 +127,6 @@ static char optlist[NOPTS];
 
 /* ============ Misc data */
 
-#ifdef __GLIBC__
-/* glibc sucks */
-static int *dash_errno;
-#undef errno
-#define errno (*dash_errno)
-#endif
-
 static char nullstr[1];                /* zero length string */
 static const char homestr[] = "HOME";
 static const char snlfmt[] = "%s\n";
@@ -12734,10 +12727,6 @@ int ash_main(int argc, char **argv)
 	struct jmploc jmploc;
 	struct stackmark smark;
 
-#ifdef __GLIBC__
-	dash_errno = __errno_location();
-#endif
-
 #if PROFILE
 	monitor(4, etext, profile_buf, sizeof(profile_buf), 50);
 #endif