Index: llvm/lib/LTO/LTOCodeGenerator.cpp
===================================================================
--- llvm/lib/LTO/LTOCodeGenerator.cpp
+++ llvm/lib/LTO/LTOCodeGenerator.cpp
@@ -261,13 +261,18 @@
     }
   }
 
+  // Setup the LDR_CNTRL variable
+  std::string LDR_CNTRL_var = "LDR_CNTRL=MAXDATA32=0xA0000000@DSA";
+  if (Optional<std::string> V = sys::Process::GetEnv("LDR_CNTRL"))
+    LDR_CNTRL_var += ("@" + *V);
+
   // Prepare inputs for the assember.
   const auto &Triple = TargetMach->getTargetTriple();
   const char *Arch = Triple.isArch64Bit() ? "-a64" : "-a32";
   std::string ObjectFileName(AssemblyFile);
   ObjectFileName[ObjectFileName.size() - 1] = 'o';
   SmallVector<StringRef, 8> Args = {
-      "/bin/env",     "LDR_CNTRL=MAXDATA32=0x80000000@${LDR_CNTRL}",
+      "/bin/env",     LDR_CNTRL_var,
       AssemblerPath,  Arch,
       "-many",        "-o",
       ObjectFileName, AssemblyFile};