[libc++] Fix a few incorrect CMake configuration options

[ldionne]

Summary

This patch fixes a few CMake options that were set using incorrect
mechanisms.

CMake's man page for the -D <var>=<value> option states: If a command in
the project sets the type to PATH or FILEPATH, then the <value> will be
converted to an absolute path. That's not what we want for most of the
paths we have as configuration options. Otherwise, using -D to set the
configuration option results in an absolute path being used, which
breaks things.

option() denotes a boolean variable, but what was desired was a
string/list variable. Fix this to prevent cmake from changing any
non-empty user provided values to 'ON'.

[ldionne]

Rebase.

libcxx/CMakeLists.txt

set(LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION "default" CACHE STRING
    value means.")
 set(TYPEINFO_COMPARISON_VALUES "default;1;2;3")
 if (NOT ("${LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION}" IN_LIST TYPEINFO_COMPARISON_VALUES))
   message(FATAL_ERROR "Value '${LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION}' is not a valid value for
                        LIBCXX_TYPEINFO_COMPARISON_IMPLEMENTATION")
 endif()
 
 set(LIBCXX_ABI_DEFINES "" CACHE STRING "A semicolon separated list of ABI macros to define in the site config header.")
-option(LIBCXX_EXTRA_SITE_DEFINES "Extra defines to add into __config_site")
+set(LIBCXX_EXTRA_SITE_DEFINES "" CACHE STRING "Extra defines to add into __config_site")
 option(LIBCXX_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF)
 
 # ABI Library options ---------------------------------------------------------
 if (MSVC)
   set(LIBCXX_DEFAULT_ABI_LIBRARY "vcruntime")
 elseif (${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD")
   set(LIBCXX_DEFAULT_ABI_LIBRARY "libcxxrt")
 else()

 
 #===============================================================================
 # Configure System
 #===============================================================================
 
 # TODO: Projects that depend on libc++ should use LIBCXX_GENERATED_INCLUDE_DIR
 # instead of hard-coding include/c++/v1.
 
-set(LIBCXX_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE PATH
+set(LIBCXX_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE STRING
     "Path where target-agnostic libc++ headers should be installed.")
-set(LIBCXX_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE PATH
+set(LIBCXX_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE STRING
     "Path where built libc++ runtime libraries should be installed.")
 
 set(LIBCXX_SHARED_OUTPUT_NAME "c++" CACHE STRING "Output name for the shared libc++ runtime library.")
 set(LIBCXX_STATIC_OUTPUT_NAME "c++" CACHE STRING "Output name for the static libc++ runtime library.")
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LLVM_DEFAULT_TARGET_TRIPLE})
   set(LIBCXX_GENERATED_INCLUDE_DIR "${LLVM_BINARY_DIR}/include/c++/v1")
   set(LIBCXX_GENERATED_MODULE_DIR "${LLVM_BINARY_DIR}/modules/c++/v1")
   set(LIBCXX_GENERATED_INCLUDE_TARGET_DIR "${LLVM_BINARY_DIR}/include/${LLVM_DEFAULT_TARGET_TRIPLE}/c++/v1")
-  set(LIBCXX_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE PATH
+  set(LIBCXX_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE STRING
       "Path where built libc++ libraries should be installed.")
-  set(LIBCXX_INSTALL_INCLUDE_TARGET_DIR "${CMAKE_INSTALL_INCLUDEDIR}/${LLVM_DEFAULT_TARGET_TRIPLE}/c++/v1" CACHE PATH
+  set(LIBCXX_INSTALL_INCLUDE_TARGET_DIR "${CMAKE_INSTALL_INCLUDEDIR}/${LLVM_DEFAULT_TARGET_TRIPLE}/c++/v1" CACHE STRING
       "Path where target-specific libc++ headers should be installed.")
   if(LIBCXX_LIBDIR_SUBDIR)
     string(APPEND LIBCXX_LIBRARY_DIR /${LIBCXX_LIBDIR_SUBDIR})
     string(APPEND LIBCXX_INSTALL_LIBRARY_DIR /${LIBCXX_LIBDIR_SUBDIR})
   endif()
 else()
   if(LLVM_LIBRARY_OUTPUT_INTDIR)
     set(LIBCXX_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
     set(LIBCXX_GENERATED_INCLUDE_DIR "${LLVM_BINARY_DIR}/include/c++/v1")
     set(LIBCXX_GENERATED_MODULE_DIR "${LLVM_BINARY_DIR}/modules/c++/v1")
   else()
     set(LIBCXX_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXX_LIBDIR_SUFFIX})
     set(LIBCXX_GENERATED_INCLUDE_DIR "${CMAKE_BINARY_DIR}/include/c++/v1")
     set(LIBCXX_GENERATED_MODULE_DIR "${CMAKE_BINARY_DIR}/modules/c++/v1")
   endif()
   set(LIBCXX_GENERATED_INCLUDE_TARGET_DIR "${LIBCXX_GENERATED_INCLUDE_DIR}")
-  set(LIBCXX_INSTALL_LIBRARY_DIR lib${LIBCXX_LIBDIR_SUFFIX} CACHE PATH
+  set(LIBCXX_INSTALL_LIBRARY_DIR lib${LIBCXX_LIBDIR_SUFFIX} CACHE STRING
       "Path where built libc++ libraries should be installed.")
-  set(LIBCXX_INSTALL_INCLUDE_TARGET_DIR "${LIBCXX_INSTALL_INCLUDE_DIR}" CACHE PATH
+  set(LIBCXX_INSTALL_INCLUDE_TARGET_DIR "${LIBCXX_INSTALL_INCLUDE_DIR}" CACHE STRING
       "Path where target-specific libc++ headers should be installed.")
 endif()
 
 file(MAKE_DIRECTORY "${LIBCXX_BINARY_INCLUDE_DIR}")
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXX_LIBRARY_DIR})

libcxxabi/CMakeLists.txt

 set(LIBCXXABI_LIBDIR_SUFFIX "${LLVM_LIBDIR_SUFFIX}" CACHE STRING
     "Define suffix of library directory name (32/64)")
 option(LIBCXXABI_INSTALL_HEADERS "Install the libc++abi headers." ON)
 option(LIBCXXABI_INSTALL_LIBRARY "Install the libc++abi library." ON)
 
 set(LIBCXXABI_SHARED_OUTPUT_NAME "c++abi" CACHE STRING "Output name for the shared libc++abi runtime library.")
 set(LIBCXXABI_STATIC_OUTPUT_NAME "c++abi" CACHE STRING "Output name for the static libc++abi runtime library.")
 
-set(LIBCXXABI_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE PATH "Path to install the libc++abi headers at.")
+set(LIBCXXABI_INSTALL_INCLUDE_DIR "${CMAKE_INSTALL_INCLUDEDIR}/c++/v1" CACHE STRING "Path to install the libc++abi headers at.")
 
 if(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBCXXABI_GENERATED_INCLUDE_DIR "${LLVM_BINARY_DIR}/include/c++/v1")
 else()
   set(LIBCXXABI_GENERATED_INCLUDE_DIR "${CMAKE_BINARY_DIR}/include/c++/v1")
 endif()
 
 # TODO: Remove this after branching for LLVM 15

 
 # Add path for custom modules
 set(CMAKE_MODULE_PATH
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
   ${CMAKE_MODULE_PATH}
   )
 
-set(LIBCXXABI_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE PATH
+set(LIBCXXABI_INSTALL_RUNTIME_DIR "${CMAKE_INSTALL_BINDIR}" CACHE STRING
     "Path where built libc++abi runtime libraries should be installed.")
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(LIBCXXABI_HEADER_DIR ${LLVM_BINARY_DIR})
   set(LIBCXXABI_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LLVM_DEFAULT_TARGET_TRIPLE})
-  set(LIBCXXABI_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE PATH
+  set(LIBCXXABI_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE STRING
       "Path where built libc++abi libraries should be installed.")
   if(LIBCXX_LIBDIR_SUBDIR)
     string(APPEND LIBCXXABI_LIBRARY_DIR /${LIBCXXABI_LIBDIR_SUBDIR})
     string(APPEND LIBCXXABI_INSTALL_LIBRARY_DIR /${LIBCXXABI_LIBDIR_SUBDIR})
   endif()
 else()
   if(LLVM_LIBRARY_OUTPUT_INTDIR)
     set(LIBCXXABI_HEADER_DIR ${LLVM_BINARY_DIR})
     set(LIBCXXABI_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
   else()
     set(LIBCXXABI_HEADER_DIR ${CMAKE_BINARY_DIR})
     set(LIBCXXABI_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBCXXABI_LIBDIR_SUFFIX})
   endif()
-  set(LIBCXXABI_INSTALL_LIBRARY_DIR lib${LIBCXXABI_LIBDIR_SUFFIX} CACHE PATH
+  set(LIBCXXABI_INSTALL_LIBRARY_DIR lib${LIBCXXABI_LIBDIR_SUFFIX} CACHE STRING
       "Path where built libc++abi libraries should be installed.")
 endif()
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBCXXABI_LIBRARY_DIR})
 
 # By default, libcxx and libcxxabi share a library directory.