cmake: do not add zlib headers for openssl

Logic copied earlier from wolfSSL. wolfSSL requires zlib headers for its
public headers. OpenSSL does not, so stop adding zlib headers for it.

Follow-up to 1e3319a167

Closes #10878

CMakeLists.txt

@@ -586,7 +586,7 @@ function(CheckQuicSupportInOpenSSL)
       set(CMAKE_REQUIRED_INCLUDES   "${WolfSSL_INCLUDE_DIRS}")
       set(CMAKE_REQUIRED_LIBRARIES  "${WolfSSL_LIBRARIES}")
       if(HAVE_LIBZ)
-        list(APPEND CMAKE_REQUIRED_INCLUDES  "${ZLIB_INCLUDE_DIRS}")
+        list(APPEND CMAKE_REQUIRED_INCLUDES  "${ZLIB_INCLUDE_DIRS}")  # Public wolfSSL headers require zlib headers
         list(APPEND CMAKE_REQUIRED_LIBRARIES "${ZLIB_LIBRARIES}")
       endif()
       if(WIN32)
@@ -598,7 +598,6 @@ function(CheckQuicSupportInOpenSSL)
       set(CMAKE_REQUIRED_INCLUDES   "${OPENSSL_INCLUDE_DIR}")
       set(CMAKE_REQUIRED_LIBRARIES  "${OPENSSL_LIBRARIES}")
       if(HAVE_LIBZ)
-        list(APPEND CMAKE_REQUIRED_INCLUDES  "${ZLIB_INCLUDE_DIRS}")
         list(APPEND CMAKE_REQUIRED_LIBRARIES "${ZLIB_LIBRARIES}")
       endif()
       if(WIN32)