[Buildroot] [PATCH 1/3] toolchain: add hidden BR2_TOOLCHAIN_HAS_SSP_STRONG boolean

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

This will allow toolchain to indicate if they support
-fstack-protector-strong or not.

Whenever the gcc version is >= 4.9, we always have SSP_STRONG support
if we have SSP support. However, some toolchains older than gcc 4.9
might have backported SSP_STRONG support, which is why we cannot rely
just on BR2_TOOLCHAIN_GCC_AT_LEAST_4_9.

Having this "default" value allows to avoid adding a "select
BR2_TOOLCHAIN_HAS_SSP_STRONG" in the internal toolchain logic plus in
almost external toolchains. But it allows custom external toolchains
that are pre-4.9 to potentially declare that they support strong SSP.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
---
 toolchain/Config.in | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/toolchain/Config.in b/toolchain/Config.in
index 973c03254f..87509f3d64 100644
--- a/toolchain/Config.in
+++ b/toolchain/Config.in
@@ -189,6 +189,10 @@ config BR2_TOOLCHAIN_HAS_THREADS_NPTL
 config BR2_TOOLCHAIN_HAS_SSP
 	bool
 
+config BR2_TOOLCHAIN_HAS_SSP_STRONG
+	bool
+	default y if BR2_TOOLCHAIN_HAS_SSP && BR2_TOOLCHAIN_GCC_AT_LEAST_4_9
+
 config BR2_TOOLCHAIN_HAS_UCONTEXT
 	bool
 
-- 
2.24.1