Add option to just install the library target

Signed-off-by: Kai-Uwe Hermann <kai-uwe.hermann@pionix.de>

Author: hikinggrass

CMakeLists.txt

@@ -15,6 +15,7 @@ option(BUILD_TESTING "Run unit tests" OFF)
 option(CMAKE_RUN_CLANG_TIDY "Run clang-tidy" OFF)
 option(LIBOCPP_BUILD_EXAMPLES "Build charge_point and central_system binaries." OFF)
 option(OCPP_INSTALL "Install the library (shared data might be installed anyway)" ${EVC_MAIN_PROJECT})
+option(LIBOCPP_INSTALL_LIBRARY "Install the libocpp library (for example when built as a shared library)" OFF)
 
 # dependencies
 find_package(Boost COMPONENTS program_options regex system thread REQUIRED)
@@ -75,6 +76,13 @@ if (OCPP_INSTALL)
     )
 endif()
 
+if (LIBOCPP_INSTALL_LIBRARY)
+    install(
+        TARGETS ocpp
+        LIBRARY
+    )
+endif()
+
 
 if(LIBOCPP16_BUILD_EXAMPLES)
     message("Building libocpp 1.6 example binaries.")