diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3400327b50..197e94a0eb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1115,7 +1115,9 @@ if(NOT CURL_DISABLE_LDAP)
       set(HAVE_LBER_H 1)
       set(CURL_LIBS "${LDAP_LIBRARIES};${CURL_LIBS}")
       list(APPEND CURL_LIBDIRS ${LDAP_LIBRARY_DIRS})
-      set(LIBCURL_PC_REQUIRES_PRIVATE "${LDAP_PC_REQUIRES};${LIBCURL_PC_REQUIRES_PRIVATE}")
+      if(LDAP_PC_REQUIRES)
+        set(LIBCURL_PC_REQUIRES_PRIVATE "${LDAP_PC_REQUIRES};${LIBCURL_PC_REQUIRES_PRIVATE}")
+      endif()
       include_directories(SYSTEM ${LDAP_INCLUDE_DIRS})
       link_directories(${LDAP_LIBRARY_DIRS})
       if(LDAP_CFLAGS)