[libc] Delete ftw/nftw header files and implementation

The implementations weren't being compiled in, so why have the headers.

Change-Id: I58f8980e943aad253e65514998bac42c6c64058a

zircon/system/ulib/c/BUILD.gn

@@ -177,7 +177,6 @@ library("c") {
             "float.h",
             "fmtmsg.h",
             "fnmatch.h",
-            "ftw.h",
             "getopt.h",
             "glob.h",
             "grp.h",

zircon/third_party/ulib/musl/include/ftw.h

-#ifndef SYSROOT_FTW_H_
-#define SYSROOT_FTW_H_
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#include <features.h>
-#include <sys/stat.h>
-
-#define FTW_F 1
-#define FTW_D 2
-#define FTW_DNR 3
-#define FTW_NS 4
-#define FTW_SL 5
-#define FTW_DP 6
-#define FTW_SLN 7
-
-#define FTW_PHYS 1
-#define FTW_MOUNT 2
-#define FTW_CHDIR 4
-#define FTW_DEPTH 8
-
-struct FTW {
-    int base;
-    int level;
-};
-
-int ftw(const char*, int (*)(const char*, const struct stat*, int), int);
-int nftw(const char*, int (*)(const char*, const struct stat*, int, struct FTW*), int, int);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif // SYSROOT_FTW_H_

zircon/third_party/ulib/musl/src/legacy/ftw.c

-#include <ftw.h>
-
-int ftw(const char* path, int (*fn)(const char*, const struct stat*, int), int fd_limit) {
-    /* The following cast assumes that calling a function with one
-     * argument more than it needs behaves as expected. This is
-     * actually undefined, but works on all real-world machines. */
-    return nftw(path, (int (*)(const char*, const struct stat*, int, struct FTW*))fn, fd_limit, FTW_PHYS);
-}

zircon/third_party/ulib/musl/src/misc/nftw.c

-#include <dirent.h>
-#include <errno.h>
-#include <ftw.h>
-#include <limits.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-struct history {
-    struct history* chain;
-    dev_t dev;
-    ino_t ino;
-    int level;
-    int base;
-};
-
-#undef dirfd
-#define dirfd(d) (*(int*)d)
-
-static int do_nftw(char* path, int (*fn)(const char*, const struct stat*, int, struct FTW*),
-                   int fd_limit, int flags, struct history* h) {
-    size_t l = strlen(path), j = l && path[l - 1] == '/' ? l - 1 : l;
-    struct stat st;
-    struct history new;
-    int type;
-    int r;
-    struct FTW lev;
-    char* name;
-
-    if ((flags & FTW_PHYS) ? lstat(path, &st) : stat(path, &st) < 0) {
-        if (!(flags & FTW_PHYS) && errno == ENOENT && !lstat(path, &st))
-            type = FTW_SLN;
-        else if (errno != EACCES)
-            return -1;
-        else
-            type = FTW_NS;
-    } else if (S_ISDIR(st.st_mode)) {
-        if (access(path, R_OK) < 0)
-            type = FTW_DNR;
-        else if (flags & FTW_DEPTH)
-            type = FTW_DP;
-        else
-            type = FTW_D;
-    } else if (S_ISLNK(st.st_mode)) {
-        if (flags & FTW_PHYS)
-            type = FTW_SL;
-        else
-            type = FTW_SLN;
-    } else {
-        type = FTW_F;
-    }
-
-    if ((flags & FTW_MOUNT) && h && st.st_dev != h->dev)
-        return 0;
-
-    new.chain = h;
-    new.dev = st.st_dev;
-    new.ino = st.st_ino;
-    new.level = h ? h->level + 1 : 0;
-    new.base = l + 1;
-
-    lev.level = new.level;
-    lev.base = h ? h->base : (name = strrchr(path, '/')) ? name - path : 0;
-
-    if (!(flags & FTW_DEPTH) && (r = fn(path, &st, type, &lev)))
-        return r;
-
-    for (; h; h = h->chain)
-        if (h->dev == st.st_dev && h->ino == st.st_ino)
-            return 0;
-
-    if ((type == FTW_D || type == FTW_DP) && fd_limit) {
-        DIR* d = opendir(path);
-        if (d) {
-            struct dirent* de;
-            while ((de = readdir(d))) {
-                if (de->d_name[0] == '.' &&
-                    (!de->d_name[1] || (de->d_name[1] == '.' && !de->d_name[2])))
-                    continue;
-                if (strlen(de->d_name) >= PATH_MAX - l) {
-                    errno = ENAMETOOLONG;
-                    closedir(d);
-                    return -1;
-                }
-                path[j] = '/';
-                strcpy(path + j + 1, de->d_name);
-                if ((r = do_nftw(path, fn, fd_limit - 1, flags, &new))) {
-                    closedir(d);
-                    return r;
-                }
-            }
-            closedir(d);
-        } else if (errno != EACCES) {
-            return -1;
-        }
-    }
-
-    path[l] = 0;
-    if ((flags & FTW_DEPTH) && (r = fn(path, &st, type, &lev)))
-        return r;
-
-    return 0;
-}
-
-int nftw(const char* path, int (*fn)(const char*, const struct stat*, int, struct FTW*),
-         int fd_limit, int flags) {
-    size_t l;
-    char pathbuf[PATH_MAX + 1];
-
-    if (fd_limit <= 0)
-        return 0;
-
-    l = strlen(path);
-    if (l > PATH_MAX) {
-        errno = ENAMETOOLONG;
-        return -1;
-    }
-    memcpy(pathbuf, path, l + 1);
-
-    return do_nftw(pathbuf, fn, fd_limit, flags, NULL);
-}