llvm_5: patch sanitizers to enable w/musl

https://gitweb.gentoo.org/proj/musl.git/plain/sys-libs/compiler-rt-sanitizers/files/compiler-rt-sanitizers-5.0.0-musl-patches.patch

pkgs/development/compilers/llvm/6/llvm.nix

@@ -77,6 +77,12 @@ in stdenv.mkDerivation (rec {
     substituteInPlace unittests/Support/CMakeLists.txt \
       --replace "add_subdirectory(DynamicLibrary)" ""
     rm unittests/Support/DynamicLibrary/DynamicLibraryTest.cpp
+    patch -p1 -i ${./sanitizers-nongnu.patch} -d projects/compiler-rt
+    sed -i projects/compiler-rt/lib/sanitizer_common/sanitizer_platform_limits_posix.cc \
+      -e '1i#define _LINUX_SYSINFO_H'
+    substituteInPlace projects/compiler-rt/lib/interception/interception_linux.h \
+      --replace '!defined(__ANDROID__)' \
+                '!defined(__ANDROID__) && !SANITIZER_NONGNU'
   '';
 
   # hacky fix: created binaries need to be run before installation
@@ -112,9 +118,6 @@ in stdenv.mkDerivation (rec {
     "-DLLVM_HOST_TRIPLE=${stdenv.hostPlatform.config}"
     "-DLLVM_DEFAULT_TARGET_TRIPLE=${stdenv.targetPlatform.config}"
     "-DTARGET_TRIPLE=${stdenv.targetPlatform.config}"
-
-    "-DCOMPILER_RT_BUILD_SANITIZERS=OFF"
-    "-DCOMPILER_RT_BUILD_XRAY=OFF"
   ];
 
   postBuild = ''