Remove fake __map_file implementation (#17023)

Fixes: #16985

Author: sbc100

src/library.js

@@ -607,12 +607,6 @@ mergeInto(LibraryManager.library, {
     }
   },
 
-  __map_file__deps: ['$setErrNo'],
-  __map_file: function(pathname, size) {
-    setErrNo({{{ cDefine('EPERM') }}});
-    return -1;
-  },
-
   _MONTH_DAYS_REGULAR: [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
   _MONTH_DAYS_LEAP: [31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
 

system/lib/standalone/standalone.c

@@ -64,11 +64,6 @@ int clock_getres(clockid_t clk_id, struct timespec *tp) {
 // mmap support is nonexistent. TODO: emulate simple mmaps using
 // stdio + malloc, which is slow but may help some things?
 
-const unsigned char * __map_file(const char *pathname, size_t *size) {
-  errno = ENOSYS;
-  return NULL;
-}
-
 intptr_t _mmap_js(size_t length,
                   int prot,
                   int flags,
@@ -115,6 +110,10 @@ __attribute__((__weak__)) int __syscall_fcntl64(int fd, int cmd, ...) {
   return -ENOSYS;
 }
 
+__attribute__((__weak__)) int __syscall_fstat64(int fd, intptr_t buf) {
+  return -ENOSYS;
+}
+
 // There is no good source of entropy without an import. Make this weak so that
 // it can be replaced with a pRNG or a proper import.
 __attribute__((__weak__))

tools/system_libs.py

@@ -940,6 +940,7 @@ def get_files(self):
           'ctime_r.c',
           'timespec_get.c',
           'utime.c',
+          '__map_file.c',
         ])
     libc_files += files_in_path(
         path='system/lib/libc/musl/src/legacy',