Move the stack protector to a new "secure" directory

As part of the code refactoring to support FORTIFY_SOURCE we want
a new subdirectory "secure" to keep the files related to security.
Move the stack protector functions to this new directory.

No functional change.

Differential Review:	https://reviews.freebsd.org/D3333

lib/libc/Makefile

@@ -95,6 +95,7 @@ NOASM=
 .include "${LIBC_SRCTOP}/stdtime/Makefile.inc"
 .include "${LIBC_SRCTOP}/string/Makefile.inc"
 .include "${LIBC_SRCTOP}/sys/Makefile.inc"
+.include "${LIBC_SRCTOP}/secure/Makefile.inc"
 .include "${LIBC_SRCTOP}/rpc/Makefile.inc"
 .include "${LIBC_SRCTOP}/uuid/Makefile.inc"
 .include "${LIBC_SRCTOP}/xdr/Makefile.inc"

lib/libc/secure/Makefile.inc

+# $FreeBSD$
+#
+# libc sources related to security
+
+.PATH: ${LIBC_SRCTOP}/secure
+
+# Sources common to both syscall interfaces:
+SRCS+=	\
+	stack_protector.c \
+	stack_protector_compat.c
+
+SYM_MAPS+=    ${LIBC_SRCTOP}/secure/Symbol.map

lib/libc/secure/Symbol.map

+/*
+ * $FreeBSD$
+ */
+
+/*
+ * It'd be nice to have this automatically generated, but we don't
+ * know to what version they will eventually belong, so for now
+ * it has to be manual.
+ */
+FBSD_1.0 {
+	__chk_fail;
+	__stack_chk_fail;
+	__stack_chk_guard;
+};

lib/libc/sys/Makefile.inc

@@ -21,8 +21,6 @@ PSEUDO+= _clock_gettime.o _gettimeofday.o
 
 # Sources common to both syscall interfaces:
 SRCS+=	\
-	stack_protector.c \
-	stack_protector_compat.c \
 	__error.c \
 	interposing_table.c
 

lib/libc/sys/Symbol.map

@@ -56,7 +56,6 @@ FBSD_1.0 {
 	bind;
 	chdir;
 	chflags;
-	__chk_fail;
 	chmod;
 	chown;
 	chroot;
@@ -281,8 +280,6 @@ FBSD_1.0 {
 	sigwaitinfo;
 	socket;
 	socketpair;
-	__stack_chk_fail;
-	__stack_chk_guard;
 	stat;
 	statfs;
 	swapoff;