diff --git a/NEWS b/NEWS
index 0cc2d50baf281..33bbf62fca8bb 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,7 @@ PHP                                                                        NEWS
     other timeout implementations). (Kévin Dunglas)
   . Fixed bug GH-14003 (Broken cleanup of unfinished calls with callable convert
     parameters). (ilutov)
+  . Fixed bug GH-14013 (Erroneous dnl appended in configure). (Peter Kokot)
 
 - Fibers:
   . Fixed bug GH-13903 (ASAN false positive underflow when executing copy()).
diff --git a/build/php_cxx_compile_stdcxx.m4 b/build/php_cxx_compile_stdcxx.m4
index f8e97fce708f0..8f723266b2c4f 100644
--- a/build/php_cxx_compile_stdcxx.m4
+++ b/build/php_cxx_compile_stdcxx.m4
@@ -27,11 +27,11 @@ AC_DEFUN([PHP_CXX_COMPILE_STDCXX], [dnl
         [$1], [14], [ax_cxx_compile_alternatives="14 1y"],
         [$1], [17], [ax_cxx_compile_alternatives="17 1z"],
         [$1], [20], [ax_cxx_compile_alternatives="20"],
-        [m4_fatal([invalid first argument `$1' to PHP_CXX_COMPILE_STDCXX])])dnl
+        [m4_fatal([invalid first argument `$1' to PHP_CXX_COMPILE_STDCXX])])[]dnl
   m4_if([$2], [], [ax_cxx_compile_cxx$1_required=true],
         [$2], [mandatory], [ax_cxx_compile_cxx$1_required=true],
         [$2], [optional], [ax_cxx_compile_cxx$1_required=false],
-        [m4_fatal([invalid third argument `$2' to PHP_CXX_COMPILE_STDCXX])])dnl
+        [m4_fatal([invalid third argument `$2' to PHP_CXX_COMPILE_STDCXX])])[]dnl
   AC_LANG_PUSH([C++])dnl
   ac_success=no