toolchain-buildroot: mark eglibc as deprecated

eglibc is a dead project and has not been making any release since a
while, now that glibc is back and kicking. So let's deprecated our
eglibc support.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

toolchain/toolchain-buildroot/Config.in

@@ -49,6 +49,7 @@ config BR2_TOOLCHAIN_BUILDROOT_EGLIBC
 		   BR2_x86_64 || BR2_microblaze || BR2_powerpc64
 	depends on BR2_USE_MMU
 	depends on !BR2_STATIC_LIBS
+	depends on BR2_DEPRECATED_SINCE_2015_08
 	select BR2_TOOLCHAIN_USES_GLIBC
 	# our eglibc.mk enables RPC support
 	select BR2_TOOLCHAIN_HAS_NATIVE_RPC