diff --git a/Modules/Platform/UnixPaths.cmake b/Modules/Platform/UnixPaths.cmake
index e95da44ea4..bdf4155232 100644
--- a/Modules/Platform/UnixPaths.cmake
+++ b/Modules/Platform/UnixPaths.cmake
@@ -71,28 +71,38 @@
   /lib /lib32 /lib64 /usr/lib /usr/lib32 /usr/lib64
   )
 
-if(CMAKE_SYSROOT_COMPILE)
-  set(_cmake_sysroot_compile "${CMAKE_SYSROOT_COMPILE}")
+# Add the Nix C library paths.
+if(DEFINED ENV{NIX_CC}
+  AND IS_DIRECTORY "$ENV{NIX_CC}"
+  AND EXISTS "$ENV{NIX_CC}/nix-support/orig-libc"
+  AND EXISTS "$ENV{NIX_CC}/nix-support/orig-libc-dev")
+  file(STRINGS "$ENV{NIX_CC}/nix-support/orig-libc" _nix_cmake_libc)
+  file(STRINGS "$ENV{NIX_CC}/nix-support/orig-libc-dev" _nix_cmake_libc_dev)
 else()
-  set(_cmake_sysroot_compile "${CMAKE_SYSROOT}")
+  set(_nix_cmake_libc @libc_lib@)
+  set(_nix_cmake_libc_dev @libc_dev@)
 endif()
+list(APPEND CMAKE_SYSTEM_INCLUDE_PATH "${_nix_cmake_libc_dev}/include")
+list(APPEND CMAKE_SYSTEM_LIBRARY_PATH "${_nix_cmake_libc}/lib")
+list(APPEND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES "${_nix_cmake_libc}/lib")
 
 # Default per-language values.  These may be later replaced after
 # parsing the implicit directory information from compiler output.
 set(_CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES_INIT
   ${CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES}
-  "${_cmake_sysroot_compile}/usr/include"
+  "${_nix_cmake_libc_dev}/include"
   )
 set(_CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES_INIT
   ${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES}
-  "${_cmake_sysroot_compile}/usr/include"
+  "${_nix_cmake_libc_dev}/include"
   )
 set(_CMAKE_CUDA_IMPLICIT_INCLUDE_DIRECTORIES_INIT
   ${CMAKE_CUDA_IMPLICIT_INCLUDE_DIRECTORIES}
-  "${_cmake_sysroot_compile}/usr/include"
+  "${_nix_cmake_libc_dev}/include"
   )
 
-unset(_cmake_sysroot_compile)
+unset(_nix_cmake_libc)
+unset(_nix_cmake_libc_dev)
 
 # Reminder when adding new locations computed from environment variables
 # please make sure to keep Help/variable/CMAKE_SYSTEM_PREFIX_PATH.rst