Bug 826173 - Avoid calling close/fclose/unlink with uninitialized values in the linker. r=nfroyd

mozglue/linker/Mappable.h

@@ -114,6 +114,8 @@ private:
   {
     static void release(char *value)
     {
+      if (!value)
+        return;
       unlink(value);
       mozilla::ScopedDeleteArrayTraits<char>::release(value);
     }

mozglue/linker/Utils.h

@@ -86,7 +86,7 @@ struct AutoCloseFDTraits
 {
   typedef int type;
   static int empty() { return -1; }
-  static void release(int fd) { close(fd); }
+  static void release(int fd) { if (fd != -1) close(fd); }
 };
 typedef mozilla::Scoped<AutoCloseFDTraits> AutoCloseFD;
 
@@ -97,7 +97,7 @@ struct AutoCloseFILETraits
 {
   typedef FILE *type;
   static FILE *empty() { return NULL; }
-  static void release(FILE *f) { fclose(f); }
+  static void release(FILE *f) { if (f) fclose(f); }
 };
 typedef mozilla::Scoped<AutoCloseFILETraits> AutoCloseFILE;