diff --git a/0004-devtoolset.patch b/0004-devtoolset.patch
index 1febfe3..500d41e 100644
--- a/0004-devtoolset.patch
+++ b/0004-devtoolset.patch
@@ -1,17 +1,19 @@
---- a/tools/clang/lib/Driver/ToolChains.cpp	2014-08-27 22:07:31.000000000 +0200
-+++ b/tools/clang/lib/Driver/ToolChains.cpp	2014-09-08 02:51:38.197987523 +0200
-@@ -1249,8 +1249,13 @@
-     Prefixes.push_back(D.InstalledDir + "/..");
- 
+--- a/tools/clang/lib/Driver/ToolChains.cpp
++++ b/tools/clang/lib/Driver/ToolChains.cpp
+@@ -1223,6 +1223,18 @@
      // And finally in /usr.
--    if (D.SysRoot.empty())
-+    if (D.SysRoot.empty()) {
-+      Prefixes.push_back("/opt/rh/devtoolset-3/root/usr");
-+      Prefixes.push_back("/opt/rh/devtoolset-2/root/usr");
-+      Prefixes.push_back("/opt/rh/devtoolset-1.1/root/usr");
-+      Prefixes.push_back("/opt/rh/devtoolset-1.0/root/usr");
+     if (D.SysRoot.empty())
        Prefixes.push_back("/usr");
++
++    // RedHat Developer Toolset support
++    if (const char *software_collections = getenv("CLANG_DTS_LIST")) {
++      SmallVector<StringRef, 4> Scls;
++      StringRef(software_collections).split(Scls, StringRef(" "), -1, false);
++      for (const auto &Scl : Scls) {
++        if (!Scl.startswith(StringRef("devtoolset-")))
++          continue;
++        const std::string SclPath = std::string("/opt/rh/") + Scl.str() + std::string("/root/usr");
++        Prefixes.push_back(SclPath);
++      }
 +    }
    }
- 
-   // Loop over the various components which exist and select the best GCC
diff --git a/llvm.spec b/llvm.spec
index c55c638..f3d68a6 100644
--- a/llvm.spec
+++ b/llvm.spec
@@ -49,7 +49,7 @@ Obsoletes: pure <= 0.55
 
 Name:           llvm
 Version:        %{version_base}.2
-Release:        3%{?dist}
+Release:        4%{?dist}
 Summary:        The Low Level Virtual Machine
 
 Group:          Development/Languages
@@ -671,6 +671,9 @@ exit 0
 %endif
 
 %changelog
+* Fri Jan 02 2015 Dave Johansen <davejohansen@gmail.com> 3.4.2-4
+- Adding CLANG_DTS_LIST for turning on devtoolset use at runtime
+
 * Thu Nov 20 2014 Dave Johansen <davejohansen@gmail.com> 3.4.2-3
 - Fix for CVE-2014-2893