libcxxabi: Find libunwind headers when LIBCXXABI_LIBUNWIND_INCLUDES is set

Currently, when LIBCXXABI_LIBUNWIND_INCLUDES is set via CMake arguments
then it ends up not searching the specified dir and unwind.h is not found
especially for ARM targets

This patch makes the searching synthesized directories and then set
LIBCXXABI_LIBUNWIND_INCLUDES if its there in environment

Upstream-Status: Pending
Signed-off-by: Khem Raj <raj.khem@gmail.com>

Author: kraj

libcxxabi/CMakeLists.txt

@@ -470,7 +470,7 @@ set(LIBCXXABI_LIBUNWIND_PATH "${LIBCXXABI_LIBUNWIND_PATH}" CACHE PATH
     "Specify path to libunwind source." FORCE)
 
 if (LIBCXXABI_USE_LLVM_UNWINDER OR LLVM_NATIVE_ARCH MATCHES ARM)
-  find_path(LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL libunwind.h
+  find_path(LIBCXXABI_LIBUNWIND_INCLUDES libunwind.h
     PATHS ${LIBCXXABI_LIBUNWIND_INCLUDES}
           ${LIBCXXABI_LIBUNWIND_PATH}/include
           ${CMAKE_BINARY_DIR}/${LIBCXXABI_LIBUNWIND_INCLUDES}
@@ -481,18 +481,23 @@ if (LIBCXXABI_USE_LLVM_UNWINDER OR LLVM_NATIVE_ARCH MATCHES ARM)
     NO_CMAKE_FIND_ROOT_PATH
   )
 
-  if (LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL STREQUAL "LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL-NOTFOUND")
-    set(LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL "")
+  if (LIBCXXABI_LIBUNWIND_INCLUDES STREQUAL "LIBCXXABI_LIBUNWIND_INCLUDES-NOTFOUND")
+    set(LIBCXXABI_LIBUNWIND_INCLUDES "")
   endif()
 endif()
 
-if (NOT "${LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL}" STREQUAL "")
-  include_directories("${LIBCXXABI_LIBUNWIND_INCLUDES_INTERNAL}")
+if (NOT "${LIBCXXABI_LIBUNWIND_INCLUDES}" STREQUAL "")
+  include_directories("${LIBCXXABI_LIBUNWIND_INCLUDES}")
 endif()
 
 add_custom_target(cxxabi-test-depends
   COMMENT "Build dependencies required to run the libc++abi test suite.")
 
+set(LIBCXXABI_LIBUNWIND_INCLUDES "${LIBCXXABI_LIBUNWIND_INCLUDES}" CACHE PATH
+    "Specify path to libunwind includes." FORCE)
+set(LIBCXXABI_LIBUNWIND_PATH "${LIBCXXABI_LIBUNWIND_PATH}" CACHE PATH
+    "Specify path to libunwind source." FORCE)
+
 # Add source code. This also contains all of the logic for deciding linker flags
 # soname, etc...
 add_subdirectory(include)