package/python3-cffi: add python3 host variant

Add a python3 host variant since we are adding a python3 host variant of
python-cryptography and it is dependent on this.

Signed-off-by: Donald Chan <hoiho@lab126.com>
[yann.morin.1998@free.fr:
  - drop target _DEPENDENCIES since this is a host-only package
  - also add sync comment to python-cffi
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/python-cffi/python-cffi.mk

@@ -4,6 +4,7 @@
 #
 ################################################################################
 
+# Please keep in sync with package/python3-cffi/python3-cffi.mk
 PYTHON_CFFI_VERSION = 1.14.2
 PYTHON_CFFI_SOURCE = cffi-$(PYTHON_CFFI_VERSION).tar.gz
 PYTHON_CFFI_SITE = https://files.pythonhosted.org/packages/f7/09/88bbe20b76ca76be052c366fe77aa5e3cd6e5f932766e5597fecdd95b2a8

package/python3-cffi/python3-cffi.hash

@@ -0,0 +1 @@
+../python-cffi/python-cffi.hash

package/python3-cffi/python3-cffi.mk

@@ -0,0 +1,29 @@
+################################################################################
+#
+# python3-cffi
+#
+################################################################################
+
+# Please keep in sync with package/python-cffi/python-cffi.mk
+PYTHON3_CFFI_VERSION = 1.14.2
+PYTHON3_CFFI_SOURCE = cffi-$(PYTHON3_CFFI_VERSION).tar.gz
+PYTHON3_CFFI_SITE = https://files.pythonhosted.org/packages/f7/09/88bbe20b76ca76be052c366fe77aa5e3cd6e5f932766e5597fecdd95b2a8
+PYTHON3_CFFI_SETUP_TYPE = setuptools
+PYTHON3_CFFI_LICENSE = MIT
+PYTHON3_CFFI_LICENSE_FILES = LICENSE
+
+# This host package uses pkg-config to find libffi, so we have to
+# provide the proper hints for pkg-config to behave properly for host
+# packages.
+HOST_PYTHON3_CFFI_ENV = \
+	PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 \
+	PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 \
+	PKG_CONFIG="$(PKG_CONFIG_HOST_BINARY)" \
+	PKG_CONFIG_SYSROOT_DIR="/" \
+	PKG_CONFIG_LIBDIR="$(HOST_DIR)/lib/pkgconfig:$(HOST_DIR)/share/pkgconfig"
+HOST_PYTHON3_CFFI_DEPENDENCIES = host-pkgconf host-python3-pycparser host-libffi
+
+HOST_PYTHON3_CFFI_DL_SUBDIR = python-cffi
+HOST_PYTHON3_CFFI_NEEDS_HOST_PYTHON = python3
+
+$(eval $(host-python-package))