diff --git a/llvm/lib/Support/Unix/Memory.inc b/llvm/lib/Support/Unix/Memory.inc
--- a/llvm/lib/Support/Unix/Memory.inc
+++ b/llvm/lib/Support/Unix/Memory.inc
@@ -91,13 +91,26 @@
   if (NumBytes == 0)
     return MemoryBlock();
 
-  int fd = -1;
+  // on platforms that have it we can use MAP_ANONYMOUS to get a memory mapped
+  // page without file backing, but we need a fallback by opening /dev/zero
+  // for strictly POSIX platforms instead
+  int fd =
+#if defined(MAP_ANONYMOUS) || defined(MAP_ANON)
+   -1;
+#else
+  open("/dev/zero", O_RDWR);
+  if (fd ==-1) {
+    EC = std::error_code(errno, std::generic_category());
+    return MemoryBlock();
+  }
+#endif
+  
 
-  int MMFlags = MAP_PRIVATE |
+  int MMFlags = MAP_PRIVATE 
 #ifdef MAP_ANONYMOUS
-  MAP_ANONYMOUS
-#else
-  MAP_ANON
+  | MAP_ANONYMOUS
+#elif MAP_ANON
+  | MAP_ANON
 #endif
   ; // Ends statement above
 
@@ -122,9 +135,17 @@
       return allocateMappedMemory(NumBytes, nullptr, PFlags, EC);
 
     EC = std::error_code(errno, std::generic_category());
+#if !defined(MAP_ANONYMOUS) && !defined(MAP_ANON) 
+    close(fd);
+#endif 
     return MemoryBlock();
   }
 
+#if !defined(MAP_ANONYMOUS) && !defined(MAP_ANON) 
+  close(fd);
+#endif 
+
+
   MemoryBlock Result;
   Result.Address = Addr;
   Result.Size = NumBytes;
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -157,11 +157,14 @@
   s = pv = strdup(pv);
   if (!pv)
     return nullptr;
-  while ((t = strsep(&s, ":")) != nullptr) {
-    if (test_dir(ret, t, bin) == 0) {
-      free(pv);
-      return ret;
-    }
+  char *state;
+  if ((t = strtok_r(s,":",&state)) != nullptr) {
+    do {
+      if (test_dir(ret, t, bin) == 0) {
+        free(pv);
+        return ret;
+      }
+    } while((t = strtok_r(nullptr,":",&state)) != nullptr);
   }
   free(pv);
   return nullptr;
diff --git a/llvm/lib/Support/Unix/Process.inc b/llvm/lib/Support/Unix/Process.inc
--- a/llvm/lib/Support/Unix/Process.inc
+++ b/llvm/lib/Support/Unix/Process.inc
@@ -288,7 +288,8 @@
 
   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)