--- a/Modules/Platform/UnixPaths.cmake
+++ b/Modules/Platform/UnixPaths.cmake
@@ -27,7 +27,7 @@
 # synchronized
 list(APPEND CMAKE_SYSTEM_PREFIX_PATH
   # Standard
-  /usr/local /usr /
+  /local /
 
   # CMake install location
   "${_CMAKE_INSTALL_DIR}"
@@ -45,26 +45,14 @@
   endif()
 endif()
 
-# Non "standard" but common install prefixes
-list(APPEND CMAKE_SYSTEM_PREFIX_PATH
-  /usr/X11R6
-  /usr/pkg
-  /opt
-  )
-
 # List common include file locations not under the common prefixes.
 list(APPEND CMAKE_SYSTEM_INCLUDE_PATH
   # X11
-  /usr/include/X11
+  /include/X11
   )
 
-list(APPEND CMAKE_SYSTEM_LIBRARY_PATH
-  # X11
-  /usr/lib/X11
-  )
-
 list(APPEND CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES
-  /lib /lib32 /lib64 /usr/lib /usr/lib32 /usr/lib64
+  /lib
   )
 
 if(CMAKE_SYSROOT_COMPILE)
@@ -77,15 +65,15 @@
 # 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"
+  "${_cmake_sysroot_compile}/include"
   )
 set(_CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES_INIT
   ${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES}
-  "${_cmake_sysroot_compile}/usr/include"
+  "${_cmake_sysroot_compile}/include"
   )
 set(_CMAKE_CUDA_IMPLICIT_INCLUDE_DIRECTORIES_INIT
   ${CMAKE_CUDA_IMPLICIT_INCLUDE_DIRECTORIES}
-  "${_cmake_sysroot_compile}/usr/include"
+  "${_cmake_sysroot_compile}/include"
   )
 
 unset(_cmake_sysroot_compile)
--- a/Modules/GNUInstallDirs.cmake
+++ b/Modules/GNUInstallDirs.cmake
@@ -57,7 +57,7 @@
 ``INCLUDEDIR``
   C header files (``include``)
 ``OLDINCLUDEDIR``
-  C header files for non-gcc (``/usr/include``)
+  C header files for non-gcc (``/include``)
 ``DATAROOTDIR``
   read-only architecture-independent data root (``share``)
 ``DATADIR``
@@ -188,94 +188,8 @@
   "Modifiable architecture-independent data (com)")
 _GNUInstallDirs_cache_path(CMAKE_INSTALL_LOCALSTATEDIR "var"
   "Modifiable single-machine data (var)")
-
-# We check if the variable was manually set and not cached, in order to
-# allow projects to set the values as normal variables before including
-# GNUInstallDirs to avoid having the entries cached or user-editable. It
-# replaces the "if(NOT DEFINED CMAKE_INSTALL_XXX)" checks in all the
-# other cases.
-# If CMAKE_INSTALL_LIBDIR is defined, if _libdir_set is false, then the
-# variable is a normal one, otherwise it is a cache one.
-get_property(_libdir_set CACHE CMAKE_INSTALL_LIBDIR PROPERTY TYPE SET)
-if(NOT DEFINED CMAKE_INSTALL_LIBDIR OR (_libdir_set
-    AND DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX
-    AND NOT "${_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX}" STREQUAL "${CMAKE_INSTALL_PREFIX}"))
-  # If CMAKE_INSTALL_LIBDIR is not defined, it is always executed.
-  # Otherwise:
-  #  * if _libdir_set is false it is not executed (meaning that it is
-  #    not a cache variable)
-  #  * if _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX is not defined it is
-  #    not executed
-  #  * if _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX and
-  #    CMAKE_INSTALL_PREFIX are the same string it is not executed.
-  #    _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX is updated after the
-  #    execution, of this part of code, therefore at the next inclusion
-  #    of the file, CMAKE_INSTALL_LIBDIR is defined, and the 2 strings
-  #    are equal, meaning that the if is not executed the code the
-  #    second time.
-
-  set(_LIBDIR_DEFAULT "lib")
-  # Override this default 'lib' with 'lib64' iff:
-  #  - we are on Linux system but NOT cross-compiling
-  #  - we are NOT on debian
-  #  - we are on a 64 bits system
-  # reason is: amd64 ABI: https://github.com/hjl-tools/x86-psABI/wiki/X86-psABI
-  # For Debian with multiarch, use 'lib/${CMAKE_LIBRARY_ARCHITECTURE}' if
-  # CMAKE_LIBRARY_ARCHITECTURE is set (which contains e.g. "i386-linux-gnu"
-  # and CMAKE_INSTALL_PREFIX is "/usr"
-  # See http://wiki.debian.org/Multiarch
-  if(DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX)
-    set(__LAST_LIBDIR_DEFAULT "lib")
-    # __LAST_LIBDIR_DEFAULT is the default value that we compute from
-    # _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX, not a cache entry for
-    # the value that was last used as the default.
-    # This value is used to figure out whether the user changed the
-    # CMAKE_INSTALL_LIBDIR value manually, or if the value was the
-    # default one. When CMAKE_INSTALL_PREFIX changes, the value is
-    # updated to the new default, unless the user explicitly changed it.
-  endif()
-  if (NOT DEFINED CMAKE_SYSTEM_NAME OR NOT DEFINED CMAKE_SIZEOF_VOID_P)
-    message(AUTHOR_WARNING
-      "Unable to determine default CMAKE_INSTALL_LIBDIR directory because no target architecture is known. "
-      "Please enable at least one language before including GNUInstallDirs.")
-  endif()
-  if(CMAKE_SYSTEM_NAME MATCHES "^(Linux|kFreeBSD|GNU)$"
-      AND NOT CMAKE_CROSSCOMPILING
-      AND NOT EXISTS "/etc/alpine-release"
-      AND NOT EXISTS "/etc/arch-release")
-    if (EXISTS "/etc/debian_version") # is this a debian system ?
-      if(CMAKE_LIBRARY_ARCHITECTURE)
-        if("${CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/?$")
-          set(_LIBDIR_DEFAULT "lib/${CMAKE_LIBRARY_ARCHITECTURE}")
-        endif()
-        if(DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX
-            AND "${_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX}" MATCHES "^/usr/?$")
-          set(__LAST_LIBDIR_DEFAULT "lib/${CMAKE_LIBRARY_ARCHITECTURE}")
-        endif()
-      endif()
-    else() # not debian, rely on CMAKE_SIZEOF_VOID_P:
-      if("${CMAKE_SIZEOF_VOID_P}" EQUAL "8")
-        set(_LIBDIR_DEFAULT "lib64")
-        if(DEFINED _GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX)
-          set(__LAST_LIBDIR_DEFAULT "lib64")
-        endif()
-      endif()
-    endif()
-  endif()
-  if(NOT DEFINED CMAKE_INSTALL_LIBDIR)
-    set(CMAKE_INSTALL_LIBDIR "${_LIBDIR_DEFAULT}" CACHE PATH "Object code libraries (${_LIBDIR_DEFAULT})")
-  elseif(DEFINED __LAST_LIBDIR_DEFAULT
-      AND "${__LAST_LIBDIR_DEFAULT}" STREQUAL "${CMAKE_INSTALL_LIBDIR}")
-    set_property(CACHE CMAKE_INSTALL_LIBDIR PROPERTY VALUE "${_LIBDIR_DEFAULT}")
-  endif()
-endif()
-_GNUInstallDirs_cache_convert_to_path(CMAKE_INSTALL_LIBDIR "Object code libraries (lib)")
-
-# Save for next run
-set(_GNUInstallDirs_LAST_CMAKE_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}" CACHE INTERNAL "CMAKE_INSTALL_PREFIX during last run")
-unset(_libdir_set)
-unset(__LAST_LIBDIR_DEFAULT)
-
+_GNUInstallDirs_cache_path(CMAKE_INSTALL_LIBDIR "lib"
+  "Object code libraries (lib)")
 _GNUInstallDirs_cache_path(CMAKE_INSTALL_INCLUDEDIR "include"
   "C header files (include)")
 _GNUInstallDirs_cache_path(CMAKE_INSTALL_OLDINCLUDEDIR "/usr/include"