cmake: make pre-built library discoverable via CMake configuration files

Co-Authored-By: Someone Serge <sergei.kozlukov@aalto.fi>

Author: Connor Baker

.gitignore

@@ -1,6 +1,7 @@
 /.clangd
 /compile_commands.json
 *.cmake
+!nanothreadConfig.cmake
 CMakeCache.txt
 CMakeFiles
 Makefile

CMakeLists.txt

@@ -65,11 +65,41 @@ endif()
 target_include_directories(nanothread
   PUBLIC
   $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
-  $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>)
+  $<INSTALL_INTERFACE:include>)
 
 target_compile_definitions(nanothread PRIVATE -DNANOTHREAD_BUILD=1)
 set_target_properties(nanothread PROPERTIES INTERPROCEDURAL_OPTIMIZATION_RELEASE TRUE)
 
 if (NANOTHREAD_ENABLE_TESTS)
    add_subdirectory(tests)
 endif()
+
+configure_file(nanothreadConfig.cmake "${CMAKE_CURRENT_BINARY_DIR}/nanothread/nanothreadConfig.cmake" COPYONLY)
+install(
+  FILES
+    nanothreadConfig.cmake
+  DESTINATION
+    lib/cmake/nanothread
+)
+install(
+  TARGETS
+    nanothread
+  EXPORT
+    nanothreadTargets
+  INCLUDES DESTINATION
+    include
+)
+install(
+  DIRECTORY
+    include/nanothread
+  DESTINATION
+    include
+)
+install(
+  EXPORT
+    nanothreadTargets
+  FILE
+    nanothreadTargets.cmake
+  DESTINATION
+    lib/cmake/nanothread
+)

nanothreadConfig.cmake

@@ -0,0 +1 @@
+include("${CMAKE_CURRENT_LIST_DIR}/nanothreadTargets.cmake")