[CMake] Remove `CMAKE_.*_OUTPUT_DIRECTORY` (NFCI)

Summary:
Three `CMAKE_.*_OUTPUT_DIRECTORY` variables used to be set in CMake and
referenced in various other parts of the project. However, in r198205
chapuni added a note to "don't set them anymore", and any remaining
references to them were subsequently removed in r198316 and r199592.

Now that the variables are no longer used anywhere, remove them, along
with the comments advising against using them any longer.

Test Plan:
I ran `check-all` and confirmed the tests built and passed.

Reviewers: beanz, chapuni

Reviewed By: beanz

Subscribers: mgorny

Differential Revision: https://reviews.llvm.org/D38389

llvm-svn: 314550

llvm/CMakeLists.txt

@@ -761,12 +761,6 @@ add_custom_target(srpm
   COMMAND cpack -G TGZ --config CPackSourceConfig.cmake -B ${LLVM_SRPM_DIR}/SOURCES
   COMMAND rpmbuild -bs --define '_topdir ${LLVM_SRPM_DIR}' ${LLVM_SRPM_BINARY_SPECFILE})
 
-
-# They are not referenced. See set_output_directory().
-set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/bin )
-set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
-set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
-
 if(APPLE AND DARWIN_LTO_LIBRARY)
   set(CMAKE_EXE_LINKER_FLAGS
     "${CMAKE_EXE_LINKER_FLAGS} -Wl,-lto_library -Wl,${DARWIN_LTO_LIBRARY}")

llvm/cmake/modules/AddLLVM.cmake

@@ -214,8 +214,6 @@ function(add_link_opts target_name)
 endfunction(add_link_opts)
 
 # Set each output directory according to ${CMAKE_CONFIGURATION_TYPES}.
-# Note: Don't set variables CMAKE_*_OUTPUT_DIRECTORY any more,
-# or a certain builder, for eaxample, msbuild.exe, would be confused.
 function(set_output_directory target)
   cmake_parse_arguments(ARG "" "BINARY_DIR;LIBRARY_DIR" "" ${ARGN})