Do not call the undeclared exit function.  This avoids build problems
with future compilers which do not support implicit function
declarations.

diff --git a/configure b/configure
index 229ccd453ae4487f..fdf3785ad4c5175f 100755
--- a/configure
+++ b/configure
@@ -19537,9 +19537,9 @@ int main()
       || fflush ((FILE *)0) < 0
       || (fpr = fopen ("conftest0", "r")) == (FILE *)0
       || fread (test_array, 1, 7, fpr) != 7)
-    exit (1);
+    return 1;
   else
-    exit(0); }
+    return 0; }
 _ACEOF
 rm -f conftest$ac_exeext
 if { (ac_try="$ac_link"
@@ -24022,7 +24022,7 @@ int main()
   int i;
   for (i=0; i < B; i++)
     Array[i] = i - 3;
-  exit (Array[1] != -2);
+  return Array[1] != -2;
 }
 _ACEOF
 rm -f conftest$ac_exeext
diff --git a/configure.ac b/configure.ac
index 8fb7b640864eb4a8..d1f6d7e08c6946d4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -88,9 +88,9 @@ int main()
       || fflush ((FILE *)0) < 0
       || (fpr = fopen ("conftest0", "r")) == (FILE *)0
       || fread (test_array, 1, 7, fpr) != 7)
-    exit (1);
+    return 1;
   else
-    exit(0); }]])],[AC_MSG_RESULT(yes); AC_DEFINE(HAVE_NULL_FLUSH)],[AC_MSG_RESULT(no)],[AC_MSG_RESULT(no)])
+    return 0; }]])],[AC_MSG_RESULT(yes); AC_DEFINE(HAVE_NULL_FLUSH)],[AC_MSG_RESULT(no)],[AC_MSG_RESULT(no)])
 
 # Checks for header files: ANSI C, POSIX, and nonstandard Unix headers.
 AC_HEADER_STDC
@@ -383,7 +383,7 @@ int main()
   int i;
   for (i=0; i < B; i++)
     Array[[i]] = i - 3;
-  exit (Array[[1]] != -2);
+  return Array[[1]] != -2;
 }]])],
 [ac_cv_c_gcc_strength_bug="no"],[ac_cv_c_gcc_strength_bug="yes"],[ac_cv_c_gcc_strength_bug="yes"]) )
   if test "$ac_cv_c_gcc_strength_bug" = "yes"