remove realpath stub and use musl's version instead

Signed-off-by: Joel Dice <[email protected]>

Makefile

@@ -127,6 +127,7 @@ LIBC_TOP_HALF_MUSL_SOURCES = \
         misc/getopt.c \
         misc/getopt_long.c \
         misc/getsubopt.c \
+        misc/realpath.c \
         misc/uname.c \
         misc/nftw.c \
         errno/strerror.c \

libc-bottom-half/sources/posix.c

@@ -351,13 +351,6 @@ int fstatvfs(int fd, struct statvfs *buf) {
     return -1;
 }
 
-char *realpath (const char *__restrict file_name, char *__restrict resolved_name) {
-    // TODO: We plan to support this eventually in WASI, but not yet.
-    // Meanwhile, we provide a stub so that libc++'s `<filesystem>`
-    // implementation will build unmodified.
-    return NULL;
-}
-
 // Like `access`, but with `faccessat`'s flags argument.
 int
 __wasilibc_access(const char *path, int mode, int flags)