Implement #278 in another way based on https://github.com/tinfoilboy/CTML/blob/master/CMakeLists.txt`.

Author: yhirose

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.14)
-project(cpp-peglib)
+project(peglib)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_EXTENSIONS OFF)
@@ -10,23 +10,31 @@ else()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
 endif()
 
-option(BUILD_TESTS "Build cpp-peglib tests" ON)
-
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads)
 
 if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
   set(add_link_deps Threads::Threads)
 endif()
 
-add_subdirectory(lint)
+add_library(peglib INTERFACE)
+target_include_directories(peglib INTERFACE ${CMAKE_SOURCE_DIR})
 
-add_subdirectory(example)
-# add_subdirectory(cymbol)
+option(BUILD_TESTS "Build cpp-peglib tests" ON)
+option(PEGLIB_BUILD_LINT "Build cpp-peglib lint utility" OFF)
+option(PEGLIB_BUILD_EXAMPLES "Build cpp-peglib examples" OFF)
 
 if (${BUILD_TESTS})
   add_subdirectory(test)
   enable_testing()
 endif()
 
+if (${PEGLIB_BUILD_LINT})
+  add_subdirectory(lint)
+endif()
+
+if (${PEGLIB_BUILD_EXAMPLES})
+  add_subdirectory(example)
+endif()
+
 install(FILES peglib.h DESTINATION include)