Index: llvm/trunk/lib/Support/Unix/Memory.inc
===================================================================
--- llvm/trunk/lib/Support/Unix/Memory.inc
+++ llvm/trunk/lib/Support/Unix/Memory.inc
@@ -91,9 +91,24 @@
   if (NumBytes == 0)
     return MemoryBlock();
 
-  int fd = -1;
+  // On platforms that have it, we can use MAP_ANON to get a memory-mapped
+  // page without file backing, but we need a fallback of opening /dev/zero
+  // for strictly POSIX platforms instead.
+  int fd;
+#if defined(MAP_ANON)
+  fd = -1;
+#else
+  fd = open("/dev/zero", O_RDWR);
+  if (fd == -1) {
+    EC = std::error_code(errno, std::generic_category());
+    return MemoryBlock();
+  }
+#endif
 
-  int MMFlags = MAP_PRIVATE | MAP_ANON;
+  int MMFlags = MAP_PRIVATE;
+#if defined(MAP_ANON)
+  MMFlags |= MAP_ANON;
+#endif
   int Protect = getPosixProtectionFlags(PFlags);
 
 #if defined(__NetBSD__) && defined(PROT_MPROTECT)
@@ -111,13 +126,24 @@
   void *Addr = ::mmap(reinterpret_cast<void *>(Start), NumBytes, Protect,
                       MMFlags, fd, 0);
   if (Addr == MAP_FAILED) {
-    if (NearBlock) //Try again without a near hint
+    if (NearBlock) { //Try again without a near hint
+#if !defined(MAP_ANON)
+      close(fd);
+#endif
       return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
+    }
 
     EC = std::error_code(errno, std::generic_category());
+#if !defined(MAP_ANON)
+    close(fd);
+#endif
     return MemoryBlock();
   }
 
+#if !defined(MAP_ANON)
+  close(fd);
+#endif
+
   MemoryBlock Result;
   Result.Address = Addr;
   Result.Size = NumBytes;
Index: llvm/trunk/lib/Support/Unix/Path.inc
===================================================================
--- llvm/trunk/lib/Support/Unix/Path.inc
+++ llvm/trunk/lib/Support/Unix/Path.inc
@@ -132,8 +132,6 @@
 static char *
 getprogpath(char ret[PATH_MAX], const char *bin)
 {
-  char *pv, *s, *t;
-
   /* First approach: absolute path. */
   if (bin[0] == '/') {
     if (test_dir(ret, "/", bin) == 0)
@@ -152,18 +150,21 @@
   }
 
   /* Third approach: $PATH */
+  char *pv;
   if ((pv = getenv("PATH")) == nullptr)
     return nullptr;
-  s = pv = strdup(pv);
-  if (!pv)
+  char *s = strdup(pv);
+  if (!s)
     return nullptr;
-  while ((t = strsep(&s, ":")) != nullptr) {
+  char *state;
+  for (char *t = strtok_r(s, ":", &state); t != nullptr;
+       t = strtok_r(nullptr, ":", &state)) {
     if (test_dir(ret, t, bin) == 0) {
-      free(pv);
+      free(s);
       return ret;
     }
   }
-  free(pv);
+  free(s);
   return nullptr;
 }
 #endif // __FreeBSD__ || __NetBSD__ || __FreeBSD_kernel__
Index: llvm/trunk/lib/Support/Unix/Process.inc
===================================================================
--- llvm/trunk/lib/Support/Unix/Process.inc
+++ llvm/trunk/lib/Support/Unix/Process.inc
@@ -291,7 +291,8 @@
 
   unsigned Columns = 0;
 
-#if defined(HAVE_SYS_IOCTL_H) && defined(HAVE_TERMIOS_H)
+#if defined(HAVE_SYS_IOCTL_H) && defined(HAVE_TERMIOS_H) \
+  && !(defined(_XOPEN_SOURCE) || defined(_POSIX_C_SOURCE))
   // Try to determine the width of the terminal.
   struct winsize ws;
   if (ioctl(FileID, TIOCGWINSZ, &ws) == 0)