Improve CMakeLists to allow disabling example and lint builds, also fix a warning on CMake version 3.24 and above.

CMakeLists.txt

@@ -1,6 +1,12 @@
 cmake_minimum_required(VERSION 3.14)
 project(cpp-peglib)
 
+# Avoid warning about DOWNLOAD_EXTRACT_TIMESTAMP in CMake 3.24:
+# Fix found at https://github.com/ethereum/solidity/pull/13429
+if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
+  cmake_policy(SET CMP0135 NEW)
+endif()
+
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
@@ -11,18 +17,17 @@ else()
 endif()
 
 option(PEGLIB_BUILD_TESTS "Build cpp-peglib tests" ON)
+option(PEGLIB_BUILD_LINT "Build cpp-peglib lint" ON)
+option(PEGLIB_BUILD_EXAMPLE "Build cpp-peglib examples" ON)
 
-set(THREADS_PREFER_PTHREAD_FLAG ON)
-find_package(Threads)
-
-if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
-  set(add_link_deps Threads::Threads)
-endif()
-
+if(${PEGLIB_BUILD_LINT})
 add_subdirectory(lint)
+endif()
 
+if(${PEGLIB_BUILD_EXAMPLE})
 add_subdirectory(example)
 # add_subdirectory(cymbol)
+endif()
 
 if (${PEGLIB_BUILD_TESTS})
   add_subdirectory(test)

test/CMakeLists.txt

@@ -1,6 +1,12 @@
 cmake_minimum_required(VERSION 3.14)
 project(test)
 
+# Avoid warning about DOWNLOAD_EXTRACT_TIMESTAMP in CMake 3.24:
+# Fix found at https://github.com/ethereum/solidity/pull/13429
+if (CMAKE_VERSION VERSION_GREATER_EQUAL "3.24.0")
+  cmake_policy(SET CMP0135 NEW)
+endif()
+
 include(FetchContent)
 FetchContent_Declare(
   googletest