Remove MB_CUR_MAX from our libc ffi

We no longer need this.

src/libc.c

@@ -3,14 +3,12 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
-#include <stdlib.h>     // MB_CUR_MAX
+#include <stdlib.h>
 #include <sys/mount.h>  // MNT_LOCAL
 #include <sys/resource.h>
 #include <sys/statvfs.h>  // ST_LOCAL
 #include <unistd.h>       // _CS_PATH, _PC_CASE_SENSITIVE
 
-size_t C_MB_CUR_MAX() { return MB_CUR_MAX; }
-
 uint64_t C_ST_LOCAL() {
 #if defined(ST_LOCAL)
     return ST_LOCAL;

src/libc.rs

@@ -29,7 +29,6 @@ pub fn $cvar() -> $type {
     };
 }
 
-CVAR!(C_MB_CUR_MAX, MB_CUR_MAX, usize);
 CVAR!(C_ST_LOCAL, ST_LOCAL, u64);
 CVAR!(C_MNT_LOCAL, MNT_LOCAL, u64);
 CVAR!(C_CS_PATH, _CS_PATH, i32);