Fix CFLAGS passed to mysql_config, in case makefile generator is Makefile based

scripts/install_scripts.cmake.in

@@ -2,8 +2,16 @@ SET(CMAKE_SYSTEM_NAME @CMAKE_SYSTEM_NAME@)
 SET(UNIX @UNIX@)
 SET(WIN32 @WIN32@)
 SET(MSVC @MSVC@)
-SET(CFLAGS "@CMAKE_C_FLAGS_RELWITHDEBINFO@")
-SET(CXXFLAGS "@CMAKE_CXX_FLAGS_RELWITHDEBINFO@")
+SET(CMAKE_GENERATOR "@CMAKE_GENERATOR@")
+IF(CMAKE_GENERATOR MATCHES "Makefiles")
+  # No multiconfig build - use CMAKE_C_FLAGS
+  SET(CFLAGS "@CMAKE_C_FLAGS@")
+  SET(CXXFLAGS "@CMAKE_CXX_FLAGS@")
+ELSE()
+  # Multiconfig build - use CMAKE_C_FLAGS_RELWITHDEBINFO
+  SET(CFLAGS "@CMAKE_C_FLAGS_RELWITHDEBINFO@")
+  SET(CXXFLAGS "@CMAKE_CXX_FLAGS_RELWITHDEBINFO@")
+ENDIF()
 SET(LDFLAGS "@CMAKE_SHARED_LIBRARY_LINK_FLAGS@")
 SET(mysqlclient_LIB_DEPENDS "@mysqlclient_LIB_DEPENDS@")
 SET(mysqlserver_LIB_DEPENDS "@mysqlserver_LIB_DEPENDS@")