[pstl][cmake] Use `GNUInstallDirs` to support custom installation dirs

I am breaking apart D99484 so the cause of build failures is easier to
understand.

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D117418

diff --git a/pstl/CMakeLists.txt b/pstl/CMakeLists.txt
index 181f116..8784eb0 100644 (file)
--- a/pstl/CMakeLists.txt
+++ b/pstl/CMakeLists.txt
@@ -7,6 +7,8 @@
 #===----------------------------------------------------------------------===##
 cmake_minimum_required(VERSION 3.13.4)
 
+include(GNUInstallDirs)
+
 set(PARALLELSTL_VERSION_FILE "${CMAKE_CURRENT_SOURCE_DIR}/include/pstl/internal/pstl_config.h")
 file(STRINGS "${PARALLELSTL_VERSION_FILE}" PARALLELSTL_VERSION_SOURCE REGEX "#define _PSTL_VERSION .*$")
 string(REGEX REPLACE "#define _PSTL_VERSION (.*)$" "\\1" PARALLELSTL_VERSION_SOURCE "${PARALLELSTL_VERSION_SOURCE}")
@@ -90,10 +92,10 @@ install(FILES "${CMAKE_CURRENT_BINARY_DIR}/ParallelSTLConfig.cmake"
               "${CMAKE_CURRENT_BINARY_DIR}/ParallelSTLConfigVersion.cmake"
         DESTINATION lib/cmake/ParallelSTL)
 install(DIRECTORY include/
-        DESTINATION include
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}"
         PATTERN "*.in" EXCLUDE)
 install(FILES "${PSTL_CONFIG_SITE_PATH}"
-        DESTINATION include)
+        DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
 
 add_custom_target(install-pstl
                   COMMAND "${CMAKE_COMMAND}" -P "${PROJECT_BINARY_DIR}/cmake_install.cmake" -DCOMPONENT=ParallelSTL)