sample/https-client: check for ERR_remove_thread_state() existence

Fixes: freebsd 9.2 build

CMakeLists.txt

@@ -774,7 +774,11 @@ if (NOT EVENT__DISABLE_SAMPLES)
         time-test)
 
     if (NOT EVENT__DISABLE_OPENSSL AND OPENSSL_LIBRARIES)
-         # Special sample with more than one file.
+        set(CMAKE_REQUIRED_LIBRARIES ${OPENSSL_LIBRARIES})
+        CHECK_FUNCTION_EXISTS_EX(ERR_remove_thread_state EVENT__HAVE_ERR_REMOVE_THREAD_STATE)
+        set(CMAKE_REQUIRED_LIBRARIES "")
+
+        # Special sample with more than one file.
         add_executable(https-client
             sample/https-client.c
             sample/openssl_hostname_validation.c

configure.ac

@@ -763,6 +763,10 @@ fi
 
 # check if we have and should use openssl
 AM_CONDITIONAL(OPENSSL, [test "$enable_openssl" != "no" && test "$have_openssl" = "yes"])
+if test "x$enable_openssl" = "xyes"; then
+	AC_SEARCH_LIBS([ERR_remove_thread_state], [crypto],
+		[AC_DEFINE(HAVE_ERR_REMOVE_THREAD_STATE, 1, [Define to 1 if you have ERR_remove_thread_stat().])])
+fi
 
 # Add some more warnings which we use in development but not in the
 # released versions.  (Some relevant gcc versions can't handle these.)

event-config.h.cmake

@@ -496,4 +496,7 @@
 
 #cmakedefine EVENT__NEED_DLLIMPORT ${EVENT__NEED_DLLIMPORT}
 
+/* Define to 1 if you have ERR_remove_thread_stat(). */
+#cmakedefine EVENT__HAVE_ERR_REMOVE_THREAD_STATE 1
+
 #endif

sample/https-client.c

@@ -471,7 +471,11 @@ cleanup:
 	EVP_cleanup();
 	ERR_free_strings();
 
+#ifdef EVENT__HAVE_ERR_REMOVE_THREAD_STATE
 	ERR_remove_thread_state(NULL);
+#else
+	ERR_remove_state(0);
+#endif
 	CRYPTO_cleanup_all_ex_data();
 
 	sk_SSL_COMP_free(SSL_COMP_get_compression_methods());