cmake: relative paths for install()

Summary:
I discovered this while investigating more build-caching issues like facebookarchive/caffe2#1103.

> If a relative path is given it is interpreted relative to the value of the CMAKE_INSTALL_PREFIX variable.
https://cmake.org/cmake/help/v3.0/command/install.html

This is a non-functional change - it just makes the code a bit easier to read. I verified locally that the resulting install directories are identical.
Closes facebookarchive/caffe2#1111

Differential Revision: D5677328

Pulled By: Yangqing

fbshipit-source-id: 9bb1bfe85fc0bc54a9b7ce33cc31e45ea061d21e

caffe/proto/CMakeLists.txt

@@ -5,4 +5,4 @@ file(GLOB Caffe_PROTOBUF_FILES "${CMAKE_CURRENT_SOURCE_DIR}/*.proto")
 caffe2_protobuf_generate_cpp_py(Caffe_PROTO_SRCS Caffe_PROTO_HEADERS Caffe_PROTO_PY ${Caffe_PROTOBUF_FILES})
 
 add_library(Caffe_PROTO OBJECT ${Caffe_PROTO_HEADERS} ${Caffe_PROTO_SRCS})
-install(FILES ${Caffe_PROTO_HEADERS} DESTINATION ${CMAKE_INSTALL_PREFIX}/include/caffe/proto)
+install(FILES ${Caffe_PROTO_HEADERS} DESTINATION include/caffe/proto)

caffe2/CMakeLists.txt

@@ -78,7 +78,7 @@ set(Caffe2_MAIN_LIBS_ORDER ${Caffe2_MAIN_LIBS})
 # Compile exposed libraries.
 add_library(Caffe2_CPU ${Caffe2_CPU_SRCS} $<TARGET_OBJECTS:Caffe_PROTO> $<TARGET_OBJECTS:Caffe2_PROTO>)
 target_link_libraries(Caffe2_CPU ${Caffe2_DEPENDENCY_LIBS})
-install(TARGETS Caffe2_CPU DESTINATION ${CMAKE_INSTALL_PREFIX}/lib)
+install(TARGETS Caffe2_CPU DESTINATION lib)
 list(APPEND Caffe2_MAIN_LIBS_ORDER Caffe2_CPU)
 if (BUILD_SHARED_LIBS)
   list(APPEND Caffe2_MAIN_LIBS Caffe2_CPU)
@@ -108,10 +108,10 @@ endforeach()
 
 # Installing the header files
 install(DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
-        DESTINATION ${CMAKE_INSTALL_PREFIX}/include/
+        DESTINATION include
         FILES_MATCHING PATTERN "*.h")
 install(FILES ${PROJECT_BINARY_DIR}/caffe2/core/macros.h
-        DESTINATION ${CMAKE_INSTALL_PREFIX}/include/caffe2/core/)
+        DESTINATION include/caffe2/core)
 
 # ---[ CUDA library.
 if(USE_CUDA)
@@ -128,7 +128,7 @@ if(USE_CUDA)
   if (Caffe2_EXTERNAL_DEPENDENCIES)
     add_dependencies(Caffe2_GPU ${Caffe2_EXTERNAL_DEPENDENCIES})
   endif()
-  install(TARGETS Caffe2_GPU DESTINATION ${CMAKE_INSTALL_PREFIX}/lib)
+  install(TARGETS Caffe2_GPU DESTINATION lib)
   link_directories(${CMAKE_INSTALL_PREFIX}/lib)
   add_dependencies(Caffe2_GPU Caffe2_PROTO)
 endif()
@@ -149,7 +149,7 @@ if (BUILD_TEST)
       target_compile_features(${test_name} PRIVATE cxx_range_for)
     endif()
     add_test(NAME ${test_name} COMMAND $<TARGET_FILE:${test_name}>)
-    install(TARGETS ${test_name} DESTINATION ${CMAKE_INSTALL_PREFIX}/test)
+    install(TARGETS ${test_name} DESTINATION test)
   endforeach()
 endif()
 
@@ -181,9 +181,7 @@ if (BUILD_PYTHON)
         COMMAND install_name_tool -add_rpath ${CMAKE_INSTALL_PREFIX}/lib
                 $<TARGET_FILE:caffe2_pybind11_state>)
   endif()
-  install(
-      TARGETS caffe2_pybind11_state DESTINATION
-      ${CMAKE_INSTALL_PREFIX}/caffe2/python)
+  install(TARGETS caffe2_pybind11_state DESTINATION caffe2/python)
 
   if(USE_CUDA)
     add_library(caffe2_pybind11_state_gpu MODULE ${Caffe2_GPU_PYTHON_SRCS})
@@ -206,9 +204,7 @@ if (BUILD_PYTHON)
           COMMAND install_name_tool -add_rpath ${CMAKE_INSTALL_PREFIX}/lib
                   $<TARGET_FILE:caffe2_pybind11_state_gpu>)
     endif()
-    install(
-        TARGETS caffe2_pybind11_state_gpu DESTINATION
-        ${CMAKE_INSTALL_PREFIX}/caffe2/python)
+    install(TARGETS caffe2_pybind11_state_gpu DESTINATION caffe2/python)
   endif()
 
   if (MSVC AND CMAKE_GENERATOR MATCHES "Visual Studio")
@@ -267,13 +263,13 @@ if (BUILD_PYTHON)
 
   # Install commands
   # Pick up static python files
-  install(DIRECTORY ${CMAKE_BINARY_DIR}/caffe2 DESTINATION ${CMAKE_INSTALL_PREFIX}
+  install(DIRECTORY ${CMAKE_BINARY_DIR}/caffe2 DESTINATION .
           FILES_MATCHING PATTERN "*.py")
   # Caffe proto files
-  install(DIRECTORY ${CMAKE_BINARY_DIR}/caffe DESTINATION ${CMAKE_INSTALL_PREFIX}
+  install(DIRECTORY ${CMAKE_BINARY_DIR}/caffe DESTINATION .
           FILES_MATCHING PATTERN "*.py")
   # Caffe2 proto files
-  install(DIRECTORY ${CMAKE_BINARY_DIR}/caffe2 DESTINATION ${CMAKE_INSTALL_PREFIX}
+  install(DIRECTORY ${CMAKE_BINARY_DIR}/caffe2 DESTINATION .
           FILES_MATCHING PATTERN "*.py")
 endif()
 

caffe2/proto/CMakeLists.txt

@@ -5,4 +5,4 @@ file(GLOB Caffe2_PROTOBUF_FILES "${CMAKE_CURRENT_SOURCE_DIR}/*.proto")
 caffe2_protobuf_generate_cpp_py(Caffe2_PROTO_SRCS Caffe2_PROTO_HEADERS Caffe2_PROTO_PY ${Caffe2_PROTOBUF_FILES})
 
 add_library(Caffe2_PROTO OBJECT ${Caffe2_PROTO_HEADERS} ${Caffe2_PROTO_SRCS})
-install(FILES ${Caffe2_PROTO_HEADERS} DESTINATION ${CMAKE_INSTALL_PREFIX}/include/caffe2/proto)
+install(FILES ${Caffe2_PROTO_HEADERS} DESTINATION include/caffe2/proto)

cmake/Utils.cmake

@@ -443,5 +443,5 @@ function(caffe2_binary_target target_name_or_src)
   add_executable(${__target} ${__srcs})
   add_dependencies(${__target} ${Caffe2_MAIN_LIBS_ORDER})
   target_link_libraries(${__target} ${Caffe2_MAIN_LIBS} ${Caffe2_DEPENDENCY_LIBS})
-  install(TARGETS ${__target} DESTINATION ${CMAKE_INSTALL_PREFIX}/bin)
+  install(TARGETS ${__target} DESTINATION bin)
 endfunction()