Enabled C++20 if it is available (if it is not, CMake will choose an earlier version)

Author: KOLANICH

CMakeLists.txt

@@ -196,6 +196,7 @@ target_include_directories(SQLiteCpp PRIVATE
 )
 target_link_libraries(SQLiteCpp PUBLIC sqlite3)
 harden(SQLiteCpp)
+set_property(TARGET SQLiteCpp PROPERTY CXX_STANDARD 20)
 
 if (UNIX AND (CMAKE_COMPILER_IS_GNUCXX OR ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang"))
     set_target_properties(SQLiteCpp PROPERTIES COMPILE_FLAGS "-fPIC")
@@ -275,6 +276,7 @@ if (SQLITECPP_BUILD_EXAMPLES)
     # add the basic example executable
     add_executable(SQLiteCpp_example1 ${SQLITECPP_EXAMPLES})
     target_link_libraries(SQLiteCpp_example1 SQLiteCpp)
+    set_property(TARGET SQLiteCpp_example1 PROPERTY CXX_STANDARD 20)
     harden(SQLiteCpp_example1)
 
     # Link target with pthread and dl for linux
@@ -327,7 +329,7 @@ if (SQLITECPP_BUILD_TESTS)
     target_include_directories(SQLiteCpp_tests PRIVATE "${GTEST_INCLUDE_DIR}" "${sqlite3_AMALGAMATION_SOURCE_DIR}")
     target_link_libraries(SQLiteCpp_tests "${GTEST_LIBRARY}" "${GTEST_MAIN_LIBRARY}" SQLiteCpp sqlite3)
     harden(SQLiteCpp_tests)
-
+    set_property(TARGET SQLiteCpp_tests PROPERTY CXX_STANDARD 20)
     # Link target with dl for linux
     if (UNIX AND NOT APPLE)
         target_link_libraries(SQLiteCpp_tests dl)