br-ext: embed opensc for pkcs11-tool

Embed opensc package for pkcs11-tool to play with the PKCS11 TA.

Examples of using pkcs11-tool with PKCS11 TA:

  # Get tokens/slots info
  pkcs11-tool --show-info
  pkcs11-tool --list-token-slots
  pkcs11-tool --list-mechanisms

  # Initialize token and user PIN
  pkcs11-tool --init-token --label test-token --so-pin 1234567890
  pkcs11-tool --label test-token --login --so-pin 1234567890 \
              --init-pin --pin ABCDEFGHIJ

  # Generate a 2048bit RSA key
  pkcs11-tool --token-label test-token --pin ABCDEFGHIJ \
              --keypairgen --key-type RSA:2048 --id 123 --label rsa-test-key

  # List token object
  pkcs11-tool --token-label test-token --list-objects

Co-developed-by: Gábor Székely <szvgabor@gmail.com>
Signed-off-by: Gábor Székely <szvgabor@gmail.com>
Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/common.mk b/common.mk
index 28bbbd8..63a233b 100644
--- a/common.mk
+++ b/common.mk
@@ -278,6 +278,9 @@
 BR2_PACKAGE_STRACE ?= y
 BR2_TARGET_GENERIC_GETTY_PORT ?= $(if $(CFG_NW_CONSOLE_UART),ttyAMA$(CFG_NW_CONSOLE_UART),ttyAMA0)
 
+# Embed opensc for pkcs11-tool
+BR2_PACKAGE_OPENSC ?= y
+
 # All BR2_* variables from the makefile or the environment are appended to
 # ../out-br/extra.conf. All values are quoted "..." except y and n.
 double-quote = "#" # This really sets the variable to " and avoids upsetting vim's syntax highlighting