[libcxx] Unify LIBCXX_<ABI-Name>_INCLUDE_PATHS to be LIBCXX_CXX_ABI_INCLUDE_PATHS

Summary:
Clean up all the different possible CMake options for specifying the ABI include paths into one CMake option named `LIBCXX_CXX_ABI_INCLUDE_PATHS`. 
The documentation has been updated to reflect this change.

For the next week I have added explicit errors if any of the old flags is used. These errors inform users of the change and the new option to use.

Before committing the change I will announce this change on cfe-dev.

Reviewers: danalbert, mclow.lists

Reviewed By: danalbert, mclow.lists

Subscribers: jroelofs, cbergstrom, cfe-commits

Differential Revision: http://reviews.llvm.org/D5039

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@232762 91177308-0d34-0410-b5e6-96231b3b80d8

cmake/Modules/HandleLibCXXABI.cmake

@@ -15,9 +15,9 @@
 #   abidirs   : A list of relative paths to create under an include directory
 #               in the libc++ build directory.
 #
-macro(setup_abi_lib abipathvar abidefines abilib abifiles abidirs)
+macro(setup_abi_lib abidefines abilib abifiles abidirs)
   list(APPEND LIBCXX_COMPILE_FLAGS ${abidefines})
-  set(${abipathvar} "${${abipathvar}}"
+  set(LIBCXX_CXX_ABI_INCLUDE_PATHS "${LIBCXX_CXX_ABI_INCLUDE_PATHS}"
     CACHE PATH
     "Paths to C++ ABI header directories separated by ';'." FORCE
     )
@@ -33,7 +33,7 @@ macro(setup_abi_lib abipathvar abidefines abilib abifiles abidirs)
 
   foreach(fpath ${LIBCXX_ABILIB_FILES})
     set(found FALSE)
-    foreach(incpath ${${abipathvar}})
+    foreach(incpath ${LIBCXX_CXX_ABI_INCLUDE_PATHS})
       if (EXISTS "${incpath}/${fpath}")
         set(found TRUE)
         get_filename_component(dstdir ${fpath} PATH)
@@ -71,7 +71,7 @@ if ("${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "libstdc++" OR
     set(_LIBSUPCXX_DEFINES "")
     set(_LIBSUPCXX_LIBNAME supc++)
   endif()
-  setup_abi_lib("LIBCXX_LIBSUPCXX_INCLUDE_PATHS"
+  setup_abi_lib(
     "-D__GLIBCXX__ ${_LIBSUPCXX_DEFINES}"
     "${_LIBSUPCXX_LIBNAME}" "${_LIBSUPCXX_INCLUDE_FILES}" "bits"
     )
@@ -88,11 +88,11 @@ elseif ("${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "libcxxabi")
     # Assume c++abi is installed in the system, rely on -lc++abi link flag.
     set(CXXABI_LIBNAME "c++abi")
   endif()
-  setup_abi_lib("LIBCXX_LIBCXXABI_INCLUDE_PATHS" ""
+  setup_abi_lib(""
     ${CXXABI_LIBNAME} "cxxabi.h;__cxxabi_config.h" ""
     )
 elseif ("${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "libcxxrt")
-  setup_abi_lib("LIBCXX_LIBCXXRT_INCLUDE_PATHS" "-DLIBCXXRT"
+  setup_abi_lib("-DLIBCXXRT"
     "cxxrt" "cxxabi.h;unwind.h;unwind-arm.h;unwind-itanium.h" ""
     )
 elseif (NOT "${LIBCXX_CXX_ABI_LIBNAME}" STREQUAL "none")