updated for version 7.3.368
Problem:    Gcc complains about redefining _FORTIFY_SOURCE.
Solution:   Undefine it before redefining it.
diff --git a/src/auto/configure b/src/auto/configure
index e391b1c..ff2e13b 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -12483,10 +12483,10 @@
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
   fi
-        { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we need -D_FORTIFY_SOURCE=1" >&5
+          { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we need -D_FORTIFY_SOURCE=1" >&5
 $as_echo_n "checking whether we need -D_FORTIFY_SOURCE=1... " >&6; }
   if test "$gccmajor" -gt "3"; then
-    CFLAGS=`echo "$CFLAGS" | sed -e 's/-Wp,-D_FORTIFY_SOURCE=.//g' -e 's/-D_FORTIFY_SOURCE=.//g' -e 's/$/ -D_FORTIFY_SOURCE=1/'`
+    CFLAGS=`echo "$CFLAGS" | sed -e 's/-Wp,-D_FORTIFY_SOURCE=.//g' -e 's/-D_FORTIFY_SOURCE=.//g' -e 's/$/ -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1/'`
     { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
   else