botan: limit to supported CPU architectures

See src/build-data/arch/ for the list of supported CPU architectures.

Fixes:

  http://autobuild.buildroot.org/results/69f/69fdecb06a03e6a95adfab70adf8ebf45971f0da/

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

package/botan/Config.in

@@ -1,6 +1,13 @@
+config BR2_PACKAGE_BOTAN_ARCH_SUPPORTS
+	default y if BR2_arm || BR2_armeb || BR2_i386 || BR2_m68k    || \
+		BR2_mips || BR2_mipsel || BR2_mips64 || BR2_mips64el || \
+		BR2_powerpc || BR2_powerpc64 || BR2_sparc || BR2_sh  || \
+		BR2_x86_64
+
 config BR2_PACKAGE_BOTAN
 	bool "botan"
 	depends on BR2_INSTALL_LIBSTDCPP
+	depends on BR2_PACKAGE_BOTAN_ARCH_SUPPORTS
 	help
 	  Botan is a crypto library for C++
 
@@ -8,3 +15,4 @@ config BR2_PACKAGE_BOTAN
 
 comment "botan needs a toolchain w/ C++"
 	depends on !BR2_INSTALL_LIBSTDCPP
+	depends on BR2_PACKAGE_BOTAN_ARCH_SUPPORTS