macOS: Revert finding tools inside Xcode that are not in the PATH

Since commit 03ab170fe0 (OS X: Enable command-line build without tools in
PATH, 2013-08-05, v2.8.12~111^2) we find compilers such as

    /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc

when there is no corresponding compiler in the PATH.  However, modern
macOS versions always have `/usr/bin/cc` in the PATH, so this code path is
never taken (similarly for `make`).  Even if it were, the compilers in
Xcode cannot be used by build systems that do not add an `-isysroot` flag.
Instead, they should be used through the `/usr/bin/cc` wrapper, which
internally calls Xcode's compiler with a default `-isysroot` flag.

Modules/CMakeDetermineCompiler.cmake

@@ -82,27 +82,6 @@ macro(_cmake_find_compiler lang)
   endif()
   unset(_${lang}_COMPILER_HINTS)
   unset(_languages)
-
-  # Look for a make tool provided by Xcode
-  if(CMAKE_${lang}_COMPILER STREQUAL "CMAKE_${lang}_COMPILER-NOTFOUND" AND CMAKE_HOST_APPLE)
-    macro(_query_xcrun compiler_name result_var_keyword result_var)
-      if(NOT "x${result_var_keyword}" STREQUAL "xRESULT_VAR")
-        message(FATAL_ERROR "Bad arguments to macro")
-      endif()
-      execute_process(COMMAND xcrun --find ${compiler_name}
-        OUTPUT_VARIABLE _xcrun_out OUTPUT_STRIP_TRAILING_WHITESPACE
-        ERROR_VARIABLE _xcrun_err)
-      set("${result_var}" "${_xcrun_out}")
-    endmacro()
-
-    foreach(comp IN LISTS CMAKE_${lang}_COMPILER_LIST)
-      _query_xcrun("${comp}" RESULT_VAR xcrun_result)
-      if(xcrun_result)
-        set_property(CACHE CMAKE_${lang}_COMPILER PROPERTY VALUE "${xcrun_result}")
-        break()
-      endif()
-    endforeach()
-  endif()
 endmacro()
 
 macro(_cmake_find_compiler_path lang)

Modules/CMakeUnixFindMake.cmake

@@ -4,13 +4,3 @@
 
 find_program(CMAKE_MAKE_PROGRAM NAMES gmake make smake)
 mark_as_advanced(CMAKE_MAKE_PROGRAM)
-
-# Look for a make tool provided by Xcode
-if(NOT CMAKE_MAKE_PROGRAM AND CMAKE_HOST_APPLE)
-  execute_process(COMMAND xcrun --find make
-    OUTPUT_VARIABLE _xcrun_out OUTPUT_STRIP_TRAILING_WHITESPACE
-    ERROR_VARIABLE _xcrun_err)
-  if(_xcrun_out)
-    set_property(CACHE CMAKE_MAKE_PROGRAM PROPERTY VALUE "${_xcrun_out}")
-  endif()
-endif()