Revert "Don't include or link from impure paths with Nix"

This reverts commit 5cb642a.

CMakeLists.txt

@@ -30,14 +30,12 @@ set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "${CMAKE_EXE_LINKER_FLAGS_RELEASE} -fl
 
 if(APPLE)
 set(BACKEND_TARGET_TRIPLE "x86_64-apple-darwin")
-if(NOT NIX)
 include_directories(AFTER SYSTEM /usr/local/include)
 link_directories(AFTER /usr/local/lib)
 set(ENV{PKG_CONFIG_PATH} "/usr/local/opt/libffi/lib/pkgconfig")
-endif() # NOT NIX
 else()
 set(BACKEND_TARGET_TRIPLE "x86_64-unknown-linux-gnu")
-endif() # APPLE
+endif()
 
 find_package(PkgConfig REQUIRED)
 pkg_check_modules(FFI REQUIRED libffi)
@@ -101,12 +99,10 @@ macro(kllvm_add_tool name)
 
   # Link against LLVM libraries
   llvm_config(${name})
-if(APPLE AND NOT NIX)
+if(APPLE)
   target_link_libraries(${name} PUBLIC "-ljemalloc" "-Wl,-rpath /usr/local/lib" "-ldl")
-elseif(NOT NIX)
-  target_link_libraries(${name} PUBLIC "-ljemalloc" "-Wl,-rpath=/usr/local/lib" "-ldl")
 else()
-  target_link_libraries(${name} PUBLIC "-ljemalloc" "-ldl")
+  target_link_libraries(${name} PUBLIC "-ljemalloc" "-Wl,-rpath=/usr/local/lib" "-ldl")
 endif()
 endmacro(kllvm_add_tool)
 

nix/llvm-backend.nix

@@ -38,7 +38,6 @@ stdenv.mkDerivation {
   cmakeFlags = [
     ''-DCMAKE_C_COMPILER=${lib.getBin stdenv.cc}/bin/cc''
     ''-DCMAKE_CXX_COMPILER=${lib.getBin stdenv.cc}/bin/c++''
-    ''-DNIX=TRUE''
   ];
   NIX_CFLAGS_COMPILE = [ "-Wno-error" ];