diff --git a/configure.ac b/configure.ac
index 988a58ec..5909932a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -846,7 +846,7 @@ else
 	CONFIG_SCRIPTING_SPIDERMONKEY=no
 fi
 
-CXXFLAGS="$CXXFLAGS -fpermissive -Wno-sign-compare -std=gnu++17"
+CXXFLAGS="$CXXFLAGS -fpermissive -Wno-sign-compare"
 
 if test "x$CONFIG_ECMASCRIPT_SMJS" = xyes ||
    test "x$CONFIG_SCRIPTING_SPIDERMONKEY" = xyes; then
diff --git a/src/util/string.h b/src/util/string.h
index e083aa20..4504b6f4 100644
--- a/src/util/string.h
+++ b/src/util/string.h
@@ -187,10 +187,10 @@ struct string {
  * @relates string */
 #ifdef __cplusplus
 #ifdef DEBUG_MEMLEAK
-[[nodiscard]] struct string *init_string__(const char *file, int line, struct string *string);
+struct string *init_string__(const char *file, int line, struct string *string);
 #define init_string(string) init_string__(__FILE__, __LINE__, string)
 #else
-[[nodiscard]] struct string *init_string(struct string *string);
+struct string *init_string(struct string *string);
 #endif
 
 #else