toolchain: refactor Stack Smashing Protection support

This commit refactors how Stack Smashing Protection support is handled
in Buildroot:

 *) It turns the BR2_TOOLCHAIN_BUILDROOT_USE_SSP option into an option
    that only enables the SSP support in uClibc, when using the internal
    toolchain backend.

 *) It adds an hidden BR2_TOOLCHAIN_HAS_SSP option that gets enabled
    when the toolchain has SSP support. Here we have the usual dance:
    glibc/eglibc in internal/external backend always select this
    option, in the case of uClibc/internal, it gets selected when
    BR2_TOOLCHAIN_BUILDROOT_USE_SSP is enabled, in the case of
    uClibc/external, there is a new configuration option that the user
    must select (or not) depending on whether the toolchain has SSP
    support.

 *) It adds a new options BR2_ENABLE_SSP in the "Build options" menu,
    to enable the usage of SSP support, by adding
    -fstack-protector-all to the CFLAGS.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

1 files changed, 1 insertions, 1 deletions

diff --git a/package/Makefile.in b/package/Makefile.in
index 4adc33d0d5..170ad789b0 100644
--- a/package/Makefile.in
+++ b/package/Makefile.in
@@ -133,7 +133,7 @@ TARGET_CFLAGS += -msep-data
 TARGET_CXXFLAGS += -msep-data
 endif
 
-ifeq ($(BR2_TOOLCHAIN_BUILDROOT_USE_SSP),y)
+ifeq ($(BR2_ENABLE_SSP),y)
 TARGET_CFLAGS += -fstack-protector-all
 TARGET_CXXFLAGS += -fstack-protector-all
 endif