diff --git a/config.h.in b/config.h.in
index 8567a323d..2501ffd5e 100644
--- a/config.h.in
+++ b/config.h.in
@@ -107,6 +107,10 @@
    */
 #undef HAVE_DECL_ERRNO
 
+/* Define to 1 if you have the declaration of `getdelim', and to 0 if you
+   don't. */
+#undef HAVE_DECL_GETDELIM
+
 /* Define to 1 if you have the declaration of `getdomainname', and to 0 if you
    don't. */
 #undef HAVE_DECL_GETDOMAINNAME
diff --git a/configure b/configure
index d1471a48b..1ab6b8c83 100755
--- a/configure
+++ b/configure
@@ -19901,6 +19901,19 @@ if test "x$ac_cv_func_getdelim" = xyes; then :
 #define HAVE_GETDELIM 1
 _ACEOF
 
+    # Out of date gcc fixed includes may result in missing getdelim() prototype
+    ac_fn_c_check_decl "$LINENO" "getdelim" "ac_cv_have_decl_getdelim" "$ac_includes_default"
+if test "x$ac_cv_have_decl_getdelim" = xyes; then :
+  ac_have_decl=1
+else
+  ac_have_decl=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define HAVE_DECL_GETDELIM $ac_have_decl
+_ACEOF
+
+
 else
 
     case " $LIBOBJS " in
diff --git a/configure.ac b/configure.ac
index 321d24b55..bb6190688 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2680,7 +2680,10 @@ AC_CHECK_FUNCS([getgrouplist], [], [
     esac
     SUDO_APPEND_COMPAT_EXP(sudo_getgrouplist)
 ])
-AC_CHECK_FUNCS([getdelim], [], [
+AC_CHECK_FUNCS([getdelim], [
+    # Out of date gcc fixed includes may result in missing getdelim() prototype
+    AC_CHECK_DECLS([getdelim])
+], [
     AC_LIBOBJ(getdelim)
     SUDO_APPEND_COMPAT_EXP(sudo_getdelim)
     COMPAT_TEST_PROGS="${COMPAT_TEST_PROGS}${COMPAT_TEST_PROGS+ }getdelim_test"
diff --git a/include/sudo_compat.h b/include/sudo_compat.h
index 51afd6fcb..80c007b93 100644
--- a/include/sudo_compat.h
+++ b/include/sudo_compat.h
@@ -446,10 +446,13 @@ __dso_public int sudo_getgrouplist(const char *name, GETGROUPS_T basegid, GETGRO
 # undef getgrouplist
 # define getgrouplist(_a, _b, _c, _d) sudo_getgrouplist((_a), (_b), (_c), (_d))
 #endif /* GETGROUPLIST */
-#ifndef HAVE_GETDELIM
+#if !defined(HAVE_GETDELIM)
 __dso_public ssize_t sudo_getdelim(char **bufp, size_t *bufsizep, int delim, FILE *fp);
 # undef getdelim
 # define getdelim(_a, _b, _c, _d) sudo_getdelim((_a), (_b), (_c), (_d))
+#elif defined(HAVE_DECL_GETDELIM) && !HAVE_DECL_GETDELIM
+/* getdelim present in libc but missing prototype (old gcc fixed includes?) */
+ssize_t getdelim(char **bufp, size_t *bufsizep, int delim, FILE *fp);
 #endif /* HAVE_GETDELIM */
 #ifndef HAVE_GETUSERSHELL
 __dso_public char *sudo_getusershell(void);