[libunwind][cmake] Create `LIBUNWIND_INSTALL_INCLUDE_DIR` CACHE PATH

[Ericson2314]

Summary

This is created on analogy with the other CACHE PATHs in this package,
and other *_INSTALL_INCLUDE_DIR in other packages.

The branching is adjusted to deduplicate some existing code, and
likewise avoid having to define this new variable more than once.

This will be used for D99484.

[Ericson2314]

Fix typo

[Ericson2314]

Fix issue with header

[compnerd]

libunwind/CMakeLists.txt

165

A newline before this would be nice.

168

Perhaps it makes sense to use CMAKE_INSTALL_INCLUDEDIR and CMAKE_INSTALL_BINDIR to initialize the values? That will allow the standard configuration paths to fold into this. We could make these "advanced" and encourage users to prefer those (but retain these for the runtimes build configuration).

[Ericson2314]

libunwind/CMakeLists.txt

168

I was saving that for the original D99484. I've been told baby step patches is the norm, so baby steps it is!

[Ericson2314]

Add requested blank line

libunwind/CMakeLists.txt

 
 # Add path for custom modules
 set(CMAKE_MODULE_PATH
     "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
     ${CMAKE_MODULE_PATH})
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/${LLVM_DEFAULT_TARGET_TRIPLE})
+  set(LIBUNWIND_INSTALL_INCLUDE_DIR "include/${LLVM_DEFAULT_TARGET_TRIPLE}" CACHE PATH
+      "Path where built libunwind headers should be installed.")
   set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LLVM_LIBDIR_SUFFIX}/${LLVM_DEFAULT_TARGET_TRIPLE} CACHE PATH
       "Path where built libunwind libraries should be installed.")
   set(LIBUNWIND_INSTALL_RUNTIME_DIR bin CACHE PATH
       "Path where built libunwind runtime libraries should be installed.")
   if(LIBCXX_LIBDIR_SUBDIR)
     string(APPEND LIBUNWIND_LIBRARY_DIR /${LIBUNWIND_LIBDIR_SUBDIR})
     string(APPEND LIBUNWIND_INSTALL_LIBRARY_DIR /${LIBUNWIND_LIBDIR_SUBDIR})
   endif()
-elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
+else()
+  if(LLVM_LIBRARY_OUTPUT_INTDIR)
     set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
-  set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX} CACHE PATH
-      "Path where built libunwind libraries should be installed.")
-  set(LIBUNWIND_INSTALL_RUNTIME_DIR bin CACHE PATH
-      "Path where built libunwind runtime libraries should be installed.")
   else()
     set(LIBUNWIND_LIBRARY_DIR ${CMAKE_BINARY_DIR}/lib${LIBUNWIND_LIBDIR_SUFFIX})
+  endif()
+  set(LIBUNWIND_INSTALL_INCLUDE_DIR include CACHE PATH
+      "Path where built libunwind headers should be installed.")
   set(LIBUNWIND_INSTALL_LIBRARY_DIR lib${LIBUNWIND_LIBDIR_SUFFIX} CACHE PATH
       "Path where built libunwind libraries should be installed.")
   set(LIBUNWIND_INSTALL_RUNTIME_DIR bin CACHE PATH
       "Path where built libunwind runtime libraries should be installed.")
 endif()
 
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
 set(CMAKE_LIBRARY_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${LIBUNWIND_LIBRARY_DIR})
 
 set(LIBUNWIND_C_FLAGS "")
 set(LIBUNWIND_CXX_FLAGS "")
 set(LIBUNWIND_COMPILE_FLAGS "")
 set(LIBUNWIND_LINK_FLAGS "")
 
 # Include macros for adding and removing libunwind flags.
 include(HandleLibunwindFlags)

libunwind/include/CMakeLists.txt

 set(files
     __libunwind_config.h
     libunwind.h
     mach-o/compact_unwind_encoding.h
     unwind_arm_ehabi.h
     unwind_itanium.h
     unwind.h
     )
 
 add_library(unwind-headers INTERFACE)
 target_include_directories(unwind-headers INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})
 
 if(LIBUNWIND_INSTALL_HEADERS)
   foreach(file ${files})
     get_filename_component(dir ${file} DIRECTORY)
     install(FILES ${file}
-      DESTINATION "include/${dir}"
+      DESTINATION "${LIBUNWIND_INSTALL_INCLUDE_DIR}/${dir}"
       COMPONENT unwind-headers
       PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ
     )
   endforeach()
 
   if(NOT CMAKE_CONFIGURATION_TYPES)
     add_custom_target(install-unwind-headers
       DEPENDS unwind-headers
       COMMAND "${CMAKE_COMMAND}"
               -DCMAKE_INSTALL_COMPONENT=unwind-headers
               -P "${LIBUNWIND_BINARY_DIR}/cmake_install.cmake")
     add_custom_target(install-unwind-headers-stripped DEPENDS install-unwind-headers)
   endif()
 endif()