diff --git a/src/Makefile b/src/Makefile
index 5b32482..869298c 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -561,8 +561,8 @@
 #CFLAGS = -g -O2 '-DSTARTUPTIME="vimstartup"' -fno-strength-reduce -Wall -Wmissing-prototypes
 
 # Use this with GCC to check for mistakes, unused arguments, etc.
-#CFLAGS = -g -Wall -Wextra -Wmissing-prototypes -Wunreachable-code -D_FORTIFY_SOURCE=1
-#CFLAGS = -g -O2 -Wall -Wextra -Wmissing-prototypes -D_FORTIFY_SOURCE=1 -DU_DEBUG
+#CFLAGS = -g -Wall -Wextra -Wmissing-prototypes -Wunreachable-code -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1
+#CFLAGS = -g -O2 -Wall -Wextra -Wmissing-prototypes -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1 -DU_DEBUG
 #PYTHON_CFLAGS_EXTRA = -Wno-missing-field-initializers
 #MZSCHEME_CFLAGS_EXTRA = -Wno-unreachable-code -Wno-unused-parameter
 
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
 $as_echo "yes" >&6; }
   else
diff --git a/src/configure.in b/src/configure.in
index b09aa22..7a2b186 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -3584,9 +3584,10 @@
   dnl -D_FORTIFY_SOURCE=2 crashes Vim on strcpy(buf, "000") when buf is
   dnl declared as char x[1] but actually longer.  Introduced in gcc 4.0.
   dnl Also remove duplicate _FORTIFY_SOURCE arguments.
+  dnl And undefine it first to avoid a warning.
   AC_MSG_CHECKING(whether we need -D_FORTIFY_SOURCE=1)
   if test "$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/'`
     AC_MSG_RESULT(yes)
   else
     AC_MSG_RESULT(no)
diff --git a/src/version.c b/src/version.c
index 55dba1e..2e1de9b 100644
--- a/src/version.c
+++ b/src/version.c
@@ -715,6 +715,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    368,
+/**/
     367,
 /**/
     366,