Install endian.h and add that to the target include directories... (#345)

... on Windows and MacOS

When installing this library the source directory might not be
available, thus we need to install the header. However, we need to make
sure it is doesn't spill into the global include directories to shadow
and os-specific installations e.g. on Linux.

Author: urfeex

CMakeLists.txt

@@ -58,9 +58,18 @@ add_library(ur_client_library::urcl ALIAS urcl)
 target_compile_features(urcl PUBLIC cxx_std_17)
 
 if(MSVC)
-  include_directories(${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/endian)
   target_link_libraries(urcl ws2_32)
+  target_include_directories(urcl PUBLIC
+    $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/endian>
+    $<INSTALL_INTERFACE:include/${PROJECT_NAME}/3rdparty>
+  )
 else()
+  if(APPLE)
+    target_include_directories(urcl PUBLIC
+      $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/3rdparty/endian>
+      $<INSTALL_INTERFACE:include/${PROJECT_NAME}/3rdparty>
+    )
+  endif()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -pedantic")
   target_compile_options(urcl PRIVATE -Wall -Wextra -Wno-unused-parameter)
 
@@ -70,7 +79,7 @@ else()
   endif()
 endif()
 
-target_include_directories( urcl PUBLIC
+target_include_directories(urcl PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
   $<INSTALL_INTERFACE:include>
 )
@@ -102,6 +111,9 @@ install(TARGETS urcl EXPORT urcl_targets
   RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
 )
 install(DIRECTORY include/ DESTINATION include)
+install(DIRECTORY 3rdparty/endian/ DESTINATION include/${PROJECT_NAME}/3rdparty
+  FILES_MATCHING PATTERN "*.h"
+)
 
 install(EXPORT urcl_targets
   DESTINATION lib/cmake/ur_client_library