Fix build broken when no shared libcurl

Not link libcur in curlpp

Author: laoshanxi

CMakeLists.txt

@@ -1,3 +1,4 @@
+cmake_minimum_required(VERSION 3.5)
 project(curlpp)
 
 
@@ -106,7 +107,6 @@ if(CURLPP_BUILD_SHARED_LIBS)
    add_library(${PROJECT_NAME} SHARED ${HeaderFileList} ${SourceFileList})
    add_library(${PROJECT_NAME}::${PROJECT_NAME} ALIAS ${PROJECT_NAME})
    target_include_directories(${PROJECT_NAME} PUBLIC $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>)
-   target_link_libraries(${PROJECT_NAME} PUBLIC CURL::libcurl ${CONAN_LIBS})
    set_target_properties(${PROJECT_NAME} PROPERTIES SOVERSION 1 VERSION 1.0.0)
 endif()