cmake: Use GNUInstallDirs.cmake, remove cached FOO_INSTALL_DIR

This fixes the lib vs lib64 vs lib32 issue when installing

Other problem with cached BIN_INSTALL_DIR, LIB_INSTALL_DIR, etc options
is that changing official CMAKE_INSTALL_PREFIX variable has no effect.

c++/CMakeLists.txt

@@ -5,6 +5,7 @@ set(VERSION 0.6-dev)
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 
 include(CheckIncludeFileCXX)
+include(GNUInstallDirs)
 if(MSVC)
   check_include_file_cxx(initializer_list HAS_CXX11)
 else()
@@ -14,26 +15,12 @@ if(NOT HAS_CXX11)
   message(SEND_ERROR "Requires a C++11 compiler and standard library.")
 endif()
 
-# Set installation paths; these can be overridden in the cache.
-set(EXEC_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}"
-  CACHE PATH "Base installation path for executables."
-)
-set(BIN_INSTALL_DIR "${EXEC_INSTALL_PREFIX}/bin"
-  CACHE PATH "Installation directory for binaries (default: prefix/bin)."
-)
-set(LIB_INSTALL_DIR "${EXEC_INSTALL_PREFIX}/lib"
-  CACHE PATH "Installation directory for libraries (default: prefix/lib)."
-)
-set(INCLUDE_INSTALL_DIR "${EXEC_INSTALL_PREFIX}/include"
-  CACHE PATH "Installation directory for header files (default: prefix/include)."
-)
-
 # these arguments are passed to all install(TARGETS) calls
 set(INSTALL_TARGETS_DEFAULT_ARGS
   EXPORT CapnProtoTargets
-  ARCHIVE DESTINATION "${LIB_INSTALL_DIR}"
-  LIBRARY DESTINATION "${LIB_INSTALL_DIR}"
-  RUNTIME DESTINATION "${BIN_INSTALL_DIR}"
+  ARCHIVE DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+  LIBRARY DESTINATION "${CMAKE_INSTALL_LIBDIR}"
+  RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}"
 )
 
 # Options ======================================================================
@@ -101,12 +88,12 @@ write_basic_package_version_file(
   VERSION ${VERSION}
   COMPATIBILITY AnyNewerVersion
 )
-set(CONFIG_PACKAGE_LOCATION ${LIB_INSTALL_DIR}/cmake/CapnProto)
+set(CONFIG_PACKAGE_LOCATION ${CMAKE_INSTALL_LIBDIR}/cmake/CapnProto)
 
 configure_package_config_file(cmake/CapnProtoConfig.cmake.in
   ${CMAKE_CURRENT_BINARY_DIR}/CapnProtoConfig.cmake
   INSTALL_DESTINATION ${CONFIG_PACKAGE_LOCATION}
-  PATH_VARS INCLUDE_INSTALL_DIR
+  PATH_VARS CMAKE_INSTALL_FULL_INCLUDEDIR
 )
 export(EXPORT CapnProtoTargets
   FILE "${CMAKE_CURRENT_BINARY_DIR}/CapnProtoTargets.cmake"
@@ -127,27 +114,27 @@ install(FILES
 if(NOT MSVC)  # Don't install pkg-config files when building with MSVC
   # Variables for pkg-config files
   set(prefix "${CMAKE_INSTALL_PREFIX}")
-  set(exec_prefix "${EXEC_INSTALL_PREFIX}")
-  set(libdir "${LIB_INSTALL_DIR}")
-  set(includedir "${INCLUDE_INSTALL_DIR}")
+  set(exec_prefix "") # not needed since we use absolute paths in libdir and includedir
+  set(libdir "${CMAKE_INSTALL_FULL_LIBDIR}")
+  set(includedir "${CMAKE_INSTALL_FULL_INCLUDEDIR}")
   set(PTHREAD_CFLAGS "-pthread")
   set(STDLIB_FLAG)  # TODO: Unsupported
 
   configure_file(kj.pc.in "${CMAKE_CURRENT_BINARY_DIR}/kj.pc" @ONLY)
-  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/kj.pc" DESTINATION "${LIB_INSTALL_DIR}/pkgconfig")
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/kj.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
   configure_file(capnp.pc.in "${CMAKE_CURRENT_BINARY_DIR}/capnp.pc" @ONLY)
-  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/capnp.pc" DESTINATION "${LIB_INSTALL_DIR}/pkgconfig")
+  install(FILES "${CMAKE_CURRENT_BINARY_DIR}/capnp.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
   if(NOT CAPNP_LITE)
     configure_file(kj-async.pc.in "${CMAKE_CURRENT_BINARY_DIR}/kj-async.pc" @ONLY)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/kj-async.pc" DESTINATION "${LIB_INSTALL_DIR}/pkgconfig")
+    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/kj-async.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
     configure_file(capnp-rpc.pc.in "${CMAKE_CURRENT_BINARY_DIR}/capnp-rpc.pc" @ONLY)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/capnp-rpc.pc" DESTINATION "${LIB_INSTALL_DIR}/pkgconfig")
+    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/capnp-rpc.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
 
     configure_file(capnp-json.pc.in "${CMAKE_CURRENT_BINARY_DIR}/capnp-json.pc" @ONLY)
-    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/capnp-json.pc" DESTINATION "${LIB_INSTALL_DIR}/pkgconfig")
+    install(FILES "${CMAKE_CURRENT_BINARY_DIR}/capnp-json.pc" DESTINATION "${CMAKE_INSTALL_LIBDIR}/pkgconfig")
   endif()
 
   unset(STDLIB_FLAG)

c++/cmake/CapnProtoConfig.cmake.in

@@ -13,7 +13,7 @@ set(CapnProto_VERSION @VERSION@)
 
 set(CAPNP_EXECUTABLE $<TARGET_FILE:CapnProto::capnp_tool>)
 set(CAPNPC_CXX_EXECUTABLE $<TARGET_FILE:CapnProto::capnpc_cpp>)
-set(CAPNP_INCLUDE_DIRECTORY "@PACKAGE_INCLUDE_INSTALL_DIR@")
+set(CAPNP_INCLUDE_DIRECTORY "@PACKAGE_CMAKE_INSTALL_FULL_INCLUDEDIR@")
 
 # work around http://public.kitware.com/Bug/view.php?id=15258
 if(NOT _IMPORT_PREFIX)

c++/src/capnp/CMakeLists.txt

@@ -60,7 +60,7 @@ target_link_libraries(capnp kj)
 #make sure external consumers don't need to manually set the include dirs
 target_include_directories(capnp INTERFACE $<INSTALL_INTERFACE:include>)
 install(TARGETS capnp ${INSTALL_TARGETS_DEFAULT_ARGS})
-install(FILES ${capnp_headers} ${capnp_schemas} DESTINATION "${INCLUDE_INSTALL_DIR}/capnp")
+install(FILES ${capnp_headers} ${capnp_schemas} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/capnp")
 
 set(capnp-rpc_sources
   serialize-async.c++
@@ -92,7 +92,7 @@ if(NOT CAPNP_LITE)
   add_library(capnp-rpc ${capnp-rpc_sources})
   target_link_libraries(capnp-rpc kj-async kj)
   install(TARGETS capnp-rpc ${INSTALL_TARGETS_DEFAULT_ARGS})
-  install(FILES ${capnp-rpc_headers} ${capnp-rpc_schemas} DESTINATION "${INCLUDE_INSTALL_DIR}/capnp")
+  install(FILES ${capnp-rpc_headers} ${capnp-rpc_schemas} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/capnp")
 endif()
 
 # capnp-json ========================================================================
@@ -112,7 +112,7 @@ if(NOT CAPNP_LITE)
   add_library(capnp-json ${capnp-json_sources})
   target_link_libraries(capnp-json capnp kj-async kj)
   install(TARGETS capnp-json ${INSTALL_TARGETS_DEFAULT_ARGS})
-  install(FILES ${capnp-json_headers} ${capnp-json_schemas} DESTINATION "${INCLUDE_INSTALL_DIR}/capnp/compat")
+  install(FILES ${capnp-json_headers} ${capnp-json_schemas} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/capnp/compat")
 endif()
 
 # Tools/Compilers ==============================================================
@@ -133,7 +133,7 @@ if(NOT CAPNP_LITE)
   add_library(capnpc ${capnpc_sources})
   target_link_libraries(capnpc capnp kj)
   install(TARGETS capnpc ${INSTALL_TARGETS_DEFAULT_ARGS})
-  install(FILES ${capnpc_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/capnp")
+  install(FILES ${capnpc_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/capnp")
 endif()
 
 if(BUILD_TOOLS AND NOT CAPNP_LITE)
@@ -159,7 +159,7 @@ if(BUILD_TOOLS AND NOT CAPNP_LITE)
   install(TARGETS capnp_tool capnpc_cpp capnpc_capnp ${INSTALL_TARGETS_DEFAULT_ARGS})
 
   # Symlink capnpc -> capnp
-  install(CODE "execute_process(COMMAND \"${CMAKE_COMMAND}\" -E create_symlink capnp \"\$ENV{DESTDIR}${BIN_INSTALL_DIR}/capnpc\")")
+  install(CODE "execute_process(COMMAND \"${CMAKE_COMMAND}\" -E create_symlink capnp \"\$ENV{DESTDIR}${CMAKE_INSTALL_FULL_BINDIR}/capnpc\")")
 endif()  # BUILD_TOOLS AND NOT CAPNP_LITE
 
 # Tests ========================================================================

c++/src/kj/CMakeLists.txt

@@ -65,9 +65,9 @@ target_compile_definitions(kj PUBLIC ${CAPNP_LITE_FLAG})
 #make sure external consumers don't need to manually set the include dirs
 target_include_directories(kj INTERFACE $<INSTALL_INTERFACE:include>)
 install(TARGETS kj ${INSTALL_TARGETS_DEFAULT_ARGS})
-install(FILES ${kj_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj")
-install(FILES ${kj-parse_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj/parse")
-install(FILES ${kj-std_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj/std")
+install(FILES ${kj_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/kj")
+install(FILES ${kj-parse_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/kj/parse")
+install(FILES ${kj-std_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/kj/std")
 
 set(kj-test_sources
   test.c++
@@ -81,8 +81,8 @@ set(kj-test-compat_headers
 add_library(kj-test ${kj-test_sources})
 target_link_libraries(kj-test kj)
 install(TARGETS kj-test ${INSTALL_TARGETS_DEFAULT_ARGS})
-install(FILES ${kj-test_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj")
-install(FILES ${kj-test-compat_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj/compat")
+install(FILES ${kj-test_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/kj")
+install(FILES ${kj-test-compat_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/kj/compat")
 
 set(kj-async_sources
   async.c++
@@ -106,7 +106,7 @@ if(NOT CAPNP_LITE)
     target_compile_options(kj-async INTERFACE "-pthread")
   endif()
   install(TARGETS kj-async ${INSTALL_TARGETS_DEFAULT_ARGS})
-  install(FILES ${kj-async_headers} DESTINATION "${INCLUDE_INSTALL_DIR}/kj")
+  install(FILES ${kj-async_headers} DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/kj")
 endif()
 
 # Tests ========================================================================