use cmake gnuinstalldirs for install destination (#3968)

src/CMakeLists.txt

@@ -474,10 +474,12 @@ endif()
 add_dependencies(ncnn ncnn-generate-spirv)
 
 if(NCNN_INSTALL_SDK)
+    include(GNUInstallDirs)
+
     install(TARGETS ncnn EXPORT ncnn
-        ARCHIVE DESTINATION lib
-        LIBRARY DESTINATION lib
-        RUNTIME DESTINATION bin
+        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+        RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
     )
     install(FILES
         allocator.h
@@ -506,11 +508,11 @@ if(NCNN_INSTALL_SDK)
         ${CMAKE_CURRENT_BINARY_DIR}/layer_shader_type_enum.h
         ${CMAKE_CURRENT_BINARY_DIR}/layer_type_enum.h
         ${CMAKE_CURRENT_BINARY_DIR}/platform.h
-        DESTINATION include/ncnn
+        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/ncnn
     )
-    install(EXPORT ncnn DESTINATION lib/cmake/ncnn)
+    install(EXPORT ncnn DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ncnn)
     configure_file(${CMAKE_CURRENT_LIST_DIR}/../cmake/ncnnConfig.cmake.in ncnnConfig.cmake @ONLY)
-    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/ncnnConfig.cmake DESTINATION lib/cmake/ncnn)
+    install(FILES ${CMAKE_CURRENT_BINARY_DIR}/ncnnConfig.cmake DESTINATION ${CMAKE_INSTALL_LIBDIR}/cmake/ncnn)
 endif()
 
 # add ncnn and generate-spirv to a virtual project group

tools/CMakeLists.txt

@@ -1,8 +1,11 @@
 cmake_minimum_required(VERSION 3.1) # for CMAKE_CXX_STANDARD
 set(CMAKE_CXX_STANDARD 11)
+
+include(GNUInstallDirs)
 macro(ncnn_install_tool toolname)
-    install(TARGETS ${toolname} RUNTIME DESTINATION bin)
+    install(TARGETS ${toolname} RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 endmacro()
+
 if(MSVC)
     # warning C4018: '<': signed/unsigned mismatch
     # warning C4244: 'argument': conversion from 'uint64_t' to 'const unsigned int', possible loss of data

tools/pnnx/src/CMakeLists.txt

@@ -535,9 +535,10 @@ else()
 endif()
 set_target_properties(pnnx PROPERTIES MACOSX_RPATH TRUE)
 
-install(TARGETS pnnx RUNTIME DESTINATION bin)
+include(GNUInstallDirs)
+install(TARGETS pnnx RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR})
 
 if (WIN32)
     file(GLOB TORCH_DLL "${TORCH_INSTALL_PREFIX}/lib/*.dll")
-    install(FILES ${TORCH_DLL} DESTINATION bin)
+    install(FILES ${TORCH_DLL} DESTINATION ${CMAKE_INSTALL_BINDIR})
 endif()