diff --git a/pkgs/development/compilers/llvm/5/compiler-rt/compiler-rt-5-cstddef.patch b/pkgs/development/compilers/llvm/5/compiler-rt/compiler-rt-5-cstddef.patch
new file mode 100644
index 000000000000..e7abf9735b90
--- /dev/null
+++ b/pkgs/development/compilers/llvm/5/compiler-rt/compiler-rt-5-cstddef.patch
@@ -0,0 +1,10 @@
+--- a/lib/xray/xray_buffer_queue.h
++++ b/lib/xray/xray_buffer_queue.h
+@@ -17,6 +17,7 @@
+ 
+ #include "sanitizer_common/sanitizer_atomic.h"
+ #include "sanitizer_common/sanitizer_mutex.h"
++#include <cstddef>
+ #include <deque>
+ #include <unordered_set>
+ #include <utility>
diff --git a/pkgs/development/compilers/llvm/5/compiler-rt/default.nix b/pkgs/development/compilers/llvm/5/compiler-rt/default.nix
index 874540dd8c3b..f6f59bb6d99b 100644
--- a/pkgs/development/compilers/llvm/5/compiler-rt/default.nix
+++ b/pkgs/development/compilers/llvm/5/compiler-rt/default.nix
@@ -58,6 +58,7 @@ stdenv.mkDerivation {
 
     ./sys-ustat.patch
     ../../common/compiler-rt/libsanitizer-no-cyclades-9.patch
+    ./compiler-rt-5-cstddef.patch
   ] ++ lib.optional stdenv.hostPlatform.isAarch32 ./armv7l.patch;
 
   # TSAN requires XPC on Darwin, which we have no public/free source files for. We can depend on the Apple frameworks