Remove nonsense CMake for this case.

vendor/CPR/include/CMakeLists.txt

@@ -1,34 +0,0 @@
-cmake_minimum_required(VERSION 3.7)
-
-target_include_directories(cpr PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
-
-target_sources(cpr PRIVATE
-     # Header files (useful in IDEs)
-    cpr/api.h
-    cpr/auth.h
-    cpr/bearer.h
-    cpr/body.h
-    cpr/cookies.h
-    cpr/cpr.h
-    cpr/cprtypes.h
-    cpr/curlholder.h
-    cpr/curlholder.h
-    cpr/digest.h
-    cpr/error.h
-    cpr/limit_rate.h
-    cpr/max_redirects.h
-    cpr/multipart.h
-    cpr/ntlm.h
-    cpr/parameters.h
-    cpr/payload.h
-    cpr/proxies.h
-    cpr/response.h
-    cpr/session.h
-    cpr/ssl_options.h
-    cpr/timeout.h
-    cpr/unix_socket.h
-    cpr/util.h
-    cpr/verbose.h
-)
-
-install(DIRECTORY cpr DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})