diff --git a/third-party/folly/src/folly/portability/Fcntl.cpp b/third-party/folly/src/folly/portability/Fcntl.cpp
index 15b726136ce96..01cf902997b77 100644
--- a/third-party/folly/src/folly/portability/Fcntl.cpp
+++ b/third-party/folly/src/folly/portability/Fcntl.cpp
@@ -24,10 +24,6 @@
 namespace folly {
 namespace portability {
 namespace fcntl {
-int creat(char const* fn, int pm) {
-  return _creat(fn, pm);
-}
-
 int fcntl(int fd, int cmd, ...) {
   va_list args;
   int res = -1;
@@ -85,6 +81,15 @@ int fcntl(int fd, int cmd, ...) {
   return res;
 }
 
+int posix_fallocate(int fd, off_t offset, off_t len) {
+  // We'll pretend we always have enough space. We
+  // can't exactly pre-allocate on windows anyways.
+  return 0;
+}
+} // namespace fcntl
+} // namespace portability
+
+namespace fileops {
 int open(char const* fn, int of, int pm) {
   int fh;
   int realMode = _S_IREAD;
@@ -108,13 +113,6 @@ int open(char const* fn, int of, int pm) {
   errno_t res = _sopen_s(&fh, fn, of, _SH_DENYNO, realMode);
   return res ? -1 : fh;
 }
-
-int posix_fallocate(int fd, off_t offset, off_t len) {
-  // We'll pretend we always have enough space. We
-  // can't exactly pre-allocate on windows anyways.
-  return 0;
-}
-} // namespace fcntl
-} // namespace portability
+} // namespace fileops
 } // namespace folly
 #endif
diff --git a/third-party/folly/src/folly/portability/Fcntl.h b/third-party/folly/src/folly/portability/Fcntl.h
index eb149e130a4ad..79e7adffb5025 100644
--- a/third-party/folly/src/folly/portability/Fcntl.h
+++ b/third-party/folly/src/folly/portability/Fcntl.h
@@ -46,10 +46,8 @@
 namespace folly {
 namespace portability {
 namespace fcntl {
-int creat(char const* fn, int pm);
 int fcntl(int fd, int cmd, ...);
 int posix_fallocate(int fd, off_t offset, off_t len);
-int open(char const* fn, int of, int pm = 0);
 } // namespace fcntl
 } // namespace portability
 } // namespace folly
@@ -69,7 +67,7 @@ FOLLY_POP_WARNING
 namespace folly {
 namespace fileops {
 #ifdef _WIN32
-using portability::fcntl::open;
+int open(char const* fn, int of, int pm = 0);
 #else
 using ::open;
 #endif
diff --git a/third-party/folly/src/folly/portability/Stdlib.h b/third-party/folly/src/folly/portability/Stdlib.h
index db56a4e14c585..b6933de494a9c 100644
--- a/third-party/folly/src/folly/portability/Stdlib.h
+++ b/third-party/folly/src/folly/portability/Stdlib.h
@@ -62,7 +62,6 @@ int clearenv();
 #endif
 
 #ifdef _WIN32
-char* mktemp(char* tn);
 char* mkdtemp(char* tn);
 int mkstemp(char* tn);
 char* realpath(const char* path, char* resolved_path);
diff --git a/third-party/folly/src/folly/portability/SysStat.cpp b/third-party/folly/src/folly/portability/SysStat.cpp
index 5db05f6b5d1c8..fa38dd554b9fa 100644
--- a/third-party/folly/src/folly/portability/SysStat.cpp
+++ b/third-party/folly/src/folly/portability/SysStat.cpp
@@ -22,10 +22,6 @@
 namespace folly {
 namespace portability {
 namespace sysstat {
-int chmod(char const* fn, int am) {
-  return _chmod(fn, am);
-}
-
 int fchmod(int fd, mode_t mode) {
   HANDLE h = (HANDLE)_get_osfhandle(fd);
   if (h == INVALID_HANDLE_VALUE) {
@@ -60,10 +56,6 @@ int lstat(const char* path, struct stat* st) {
 int mkdir(const char* fn, int /* mode */) {
   return _mkdir(fn);
 }
-
-int umask(int md) {
-  return _umask(md);
-}
 } // namespace sysstat
 } // namespace portability
 } // namespace folly
diff --git a/third-party/folly/src/folly/portability/SysStat.h b/third-party/folly/src/folly/portability/SysStat.h
index 0a6c0bd2feecc..6fb3d5d19221b 100644
--- a/third-party/folly/src/folly/portability/SysStat.h
+++ b/third-party/folly/src/folly/portability/SysStat.h
@@ -47,11 +47,9 @@
 namespace folly {
 namespace portability {
 namespace sysstat {
-int chmod(char const* fn, int am);
 int fchmod(int fd, mode_t mode);
 int lstat(const char* path, struct stat* st);
 int mkdir(const char* fn, int mode);
-int umask(int md);
 } // namespace sysstat
 } // namespace portability
 } // namespace folly
diff --git a/third-party/folly/src/folly/portability/Unistd.cpp b/third-party/folly/src/folly/portability/Unistd.cpp
index 74f8f27b1d61f..9096cc6e55562 100644
--- a/third-party/folly/src/folly/portability/Unistd.cpp
+++ b/third-party/folly/src/folly/portability/Unistd.cpp
@@ -198,29 +198,6 @@ ProcessHandleWrapper getParentProcessHandle() {
 }
 } // namespace
 
-int access(char const* fn, int am) {
-  return _access(fn, am);
-}
-
-int chdir(const char* path) {
-  return _chdir(path);
-}
-
-int close(int fh) {
-  if (folly::portability::sockets::is_fh_socket(fh)) {
-    return netops::detail::SocketFileDescriptorMap::close(fh);
-  }
-  return _close(fh);
-}
-
-int dup(int fh) {
-  return _dup(fh);
-}
-
-int dup2(int fhs, int fhd) {
-  return _dup2(fhs, fhd);
-}
-
 int fsync(int fd) {
   HANDLE h = (HANDLE)_get_osfhandle(fd);
   if (h == INVALID_HANDLE_VALUE) {
@@ -254,10 +231,6 @@ int ftruncate(int fd, off_t len) {
   return 0;
 }
 
-char* getcwd(char* buf, int sz) {
-  return _getcwd(buf, sz);
-}
-
 int getdtablesize() {
   return _getmaxstdio();
 }
@@ -278,32 +251,14 @@ uid_t getuid() {
   return 1;
 }
 
-int isatty(int fh) {
-  return _isatty(fh);
-}
-
 int lockf(int fd, int cmd, off_t len) {
   return _locking(fd, cmd, len);
 }
 
-off_t lseek(int fh, off_t off, int orig) {
-  return _lseek(fh, off, orig);
-}
-
 off64_t lseek64(int fh, off64_t off, int orig) {
   return _lseeki64(fh, static_cast<int64_t>(off), orig);
 }
 
-int rmdir(const char* path) {
-  return _rmdir(path);
-}
-
-int pipe(int pth[2]) {
-  // We need to be able to listen to pipes with
-  // libevent, so they need to be actual sockets.
-  return socketpair(PF_UNIX, SOCK_STREAM, 0, pth);
-}
-
 ssize_t pread(int fd, void* buf, size_t count, off_t offset) {
   const bool is64Bit = false;
   return wrapPositional<is64Bit>(_read, fd, offset, buf, (unsigned int)count);
@@ -319,27 +274,6 @@ ssize_t pwrite(int fd, const void* buf, size_t count, off_t offset) {
   return wrapPositional<is64Bit>(_write, fd, offset, buf, (unsigned int)count);
 }
 
-ssize_t read(int fh, void* buf, size_t count) {
-  if (folly::portability::sockets::is_fh_socket(fh)) {
-    SOCKET s = (SOCKET)_get_osfhandle(fh);
-    if (s != INVALID_SOCKET) {
-      auto r = folly::portability::sockets::recv(fh, buf, count, 0);
-      if (r == -1 && WSAGetLastError() == WSAEWOULDBLOCK) {
-        errno = EAGAIN;
-      }
-      return r;
-    }
-  }
-  auto r = _read(fh, buf, static_cast<unsigned int>(count));
-  if (r == -1 && GetLastError() == ERROR_NO_DATA) {
-    // This only happens if the file was non-blocking and
-    // no data was present. We have to translate the error
-    // to a form that the rest of the world is expecting.
-    errno = EAGAIN;
-  }
-  return r;
-}
-
 ssize_t readlink(const char* path, char* buf, size_t buflen) {
   if (!buflen) {
     return -1;
@@ -411,6 +345,43 @@ int usleep(unsigned int ms) {
   Sleep((DWORD)(ms / 1000));
   return 0;
 }
+} // namespace unistd
+} // namespace portability
+
+namespace fileops {
+int close(int fh) {
+  if (folly::portability::sockets::is_fh_socket(fh)) {
+    return netops::detail::SocketFileDescriptorMap::close(fh);
+  }
+  return _close(fh);
+}
+
+ssize_t read(int fh, void* buf, size_t count) {
+  if (folly::portability::sockets::is_fh_socket(fh)) {
+    SOCKET s = (SOCKET)_get_osfhandle(fh);
+    if (s != INVALID_SOCKET) {
+      auto r = folly::portability::sockets::recv(fh, buf, count, 0);
+      if (r == -1 && WSAGetLastError() == WSAEWOULDBLOCK) {
+        errno = EAGAIN;
+      }
+      return r;
+    }
+  }
+  auto r = _read(fh, buf, static_cast<unsigned int>(count));
+  if (r == -1 && GetLastError() == ERROR_NO_DATA) {
+    // This only happens if the file was non-blocking and
+    // no data was present. We have to translate the error
+    // to a form that the rest of the world is expecting.
+    errno = EAGAIN;
+  }
+  return r;
+}
+
+int pipe(int pth[2]) {
+  // We need to be able to listen to pipes with
+  // libevent, so they need to be actual sockets.
+  return socketpair(PF_UNIX, SOCK_STREAM, 0, pth);
+}
 
 ssize_t write(int fh, void const* buf, size_t count) {
   if (folly::portability::sockets::is_fh_socket(fh)) {
@@ -443,8 +414,7 @@ ssize_t write(int fh, void const* buf, size_t count) {
   }
   return r;
 }
-} // namespace unistd
-} // namespace portability
+} // namespace fileops
 } // namespace folly
 
 #endif
diff --git a/third-party/folly/src/folly/portability/Unistd.h b/third-party/folly/src/folly/portability/Unistd.h
index 91e664e8c70b3..f52712c3cae24 100644
--- a/third-party/folly/src/folly/portability/Unistd.h
+++ b/third-party/folly/src/folly/portability/Unistd.h
@@ -71,25 +71,14 @@ namespace folly {
 namespace portability {
 namespace unistd {
 using off64_t = int64_t;
-int access(char const* fn, int am);
-int chdir(const char* path);
-int close(int fh);
-int dup(int fh);
-int dup2(int fhs, int fhd);
 int fsync(int fd);
 int ftruncate(int fd, off_t len);
-char* getcwd(char* buf, int sz);
 int getdtablesize();
 int getgid();
 pid_t getppid();
 int getuid();
-int isatty(int fh);
 int lockf(int fd, int cmd, off_t len);
-off_t lseek(int fh, off_t off, int orig);
 off64_t lseek64(int fh, off64_t off, int orig);
-ssize_t read(int fh, void* buf, size_t mcc);
-int rmdir(const char* path);
-int pipe(int pth[2]);
 ssize_t pread(int fd, void* buf, size_t count, off_t offset);
 ssize_t pread64(int fd, void* buf, size_t count, off64_t offset);
 ssize_t pwrite(int fd, const void* buf, size_t count, off_t offset);
@@ -99,7 +88,6 @@ unsigned int sleep(unsigned int seconds);
 long sysconf(int tp);
 int truncate(const char* path, off_t len);
 int usleep(unsigned int ms);
-ssize_t write(int fh, void const* buf, size_t count);
 } // namespace unistd
 } // namespace portability
 } // namespace folly
@@ -113,10 +101,10 @@ FOLLY_POP_WARNING
 namespace folly {
 namespace fileops {
 #ifdef _WIN32
-using folly::portability::unistd::close;
-using folly::portability::unistd::pipe;
-using folly::portability::unistd::read;
-using folly::portability::unistd::write;
+int close(int fh);
+ssize_t read(int fh, void* buf, size_t mcc);
+int pipe(int pth[2]);
+ssize_t write(int fh, void const* buf, size_t count);
 #else
 using ::close;
 using ::pipe;
diff --git a/third-party/folly/src/folly/portability/Windows.h b/third-party/folly/src/folly/portability/Windows.h
index 1e4e80167faaf..d6f4cc9f98594 100644
--- a/third-party/folly/src/folly/portability/Windows.h
+++ b/third-party/folly/src/folly/portability/Windows.h
@@ -32,24 +32,8 @@
 // disabled to ensure all of the normal names get declared properly.
 #include <stdio.h>
 
-#ifndef __STDC__
-/* nolint */
-#define __STDC__ 1
-#pragma push_macro("_CRT_DECLARE_NONSTDC_NAMES")
-#ifdef _CRT_DECLARE_NONSTDC_NAMES
-#undef _CRT_DECLARE_NONSTDC_NAMES
-#endif
-#pragma push_macro("_CRT_INTERNAL_NONSTDC_NAMES")
-#undef _CRT_INTERNAL_NONSTDC_NAMES
-#include <direct.h> // @manual nolint
-#include <io.h> // @manual nolint
-#undef __STDC__
-#pragma pop_macro("_CRT_INTERNAL_NONSTDC_NAMES")
-#pragma pop_macro("_CRT_DECLARE_NONSTDC_NAMES")
-#else
 #include <direct.h> // @manual nolint
 #include <io.h> // @manual nolint
-#endif
 
 #if defined(min) || defined(max)
 #error Windows.h needs to be included by this header, or else NOMINMAX needs \