python3: sync makefiles with python package

Technically, this just updates build details.
No functionality change to package itself.

So, no need to increase PKG_RELEASE on this change.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>

lang/python3/files/python3-host.mk

@@ -0,0 +1,96 @@
+#
+# Copyright (C) 2017 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+ifneq ($(__python3_host_mk_inc),1)
+__python3_host_mk_inc=1
+
+# For PYTHON3_VERSION
+$(call include_mk, python3-version.mk)
+
+# Compatibility fallback for older OpenWrt and LEDE versions
+ifeq ($(STAGING_DIR_HOSTPKG),)
+  $(warning STAGING_DIR_HOSTPKG is unset - falling back to $$(STAGING_DIR)/host)
+  STAGING_DIR_HOSTPKG := $(STAGING_DIR)/host
+endif
+
+HOST_PYTHON3_DIR:=$(STAGING_DIR_HOSTPKG)
+HOST_PYTHON3_INC_DIR:=$(HOST_PYTHON3_DIR)/include/python$(PYTHON3_VERSION)
+HOST_PYTHON3_LIB_DIR:=$(HOST_PYTHON3_DIR)/lib/python$(PYTHON3_VERSION)
+
+HOST_PYTHON3_PKG_DIR:=$(HOST_PYTHON3_DIR)/lib/python$(PYTHON3_VERSION)/site-packages
+
+HOST_PYTHON3_BIN:=$(HOST_PYTHON3_DIR)/bin/python$(PYTHON3_VERSION)
+
+HOST_PYTHON3PATH:=$(HOST_PYTHON3_LIB_DIR):$(HOST_PYTHON3_PKG_DIR)
+
+define HostPython3
+	if [ "$(strip $(3))" == "HOST" ]; then \
+		export PYTHONPATH="$(HOST_PYTHON3PATH)"; \
+		export PYTHONDONTWRITEBYTECODE=0; \
+	else \
+		export PYTHONPATH="$(PYTHON3PATH)"; \
+		export PYTHONDONTWRITEBYTECODE=1; \
+		export _python_sysroot="$(STAGING_DIR)"; \
+		export _python_prefix="/usr"; \
+		export _python_exec_prefix="/usr"; \
+	fi; \
+	export PYTHONOPTIMIZE=""; \
+	$(1) \
+	$(HOST_PYTHON3_BIN) $(2);
+endef
+
+# $(1) => commands to execute before running pythons script
+# $(2) => python script and its arguments
+# $(3) => additional variables
+define Build/Compile/HostPy3RunHost
+	$(call HostPython3, \
+		$(if $(1),$(1);) \
+		CC="$(HOSTCC)" \
+		CCSHARED="$(HOSTCC) $(HOST_FPIC)" \
+		CXX="$(HOSTCXX)" \
+		LD="$(HOSTCC)" \
+		LDSHARED="$(HOSTCC) -shared" \
+		CFLAGS="$(HOST_CFLAGS)" \
+		CPPFLAGS="$(HOST_CPPFLAGS) -I$(HOST_PYTHON3_INC_DIR)" \
+		LDFLAGS="$(HOST_LDFLAGS) -lpython$(PYTHON3_VERSION) -Wl$(comma)-rpath=$(STAGING_DIR_HOSTPKG)/lib" \
+		_PYTHON_HOST_PLATFORM=linux2 \
+		$(3) \
+		, \
+		$(2) \
+		, \
+		HOST \
+	)
+endef
+
+
+# $(1) => build subdir
+# $(2) => additional arguments to setup.py
+# $(3) => additional variables
+define Build/Compile/HostPy3Mod
+	$(call Build/Compile/HostPy3RunHost, \
+		cd $(HOST_BUILD_DIR)/$(strip $(1)), \
+		./setup.py $(2), \
+		$(3))
+endef
+
+define HostPy3/Compile/Default
+	$(call Build/Compile/HostPy3Mod,,\
+		install --root="$(HOST_BUILD_PREFIX)" --prefix="" \
+		--single-version-externally-managed \
+	)
+endef
+
+ifeq ($(BUILD_VARIANT),python3)
+define Host/Compile
+	$(call HostPy3/Compile/Default)
+endef
+
+define Host/Install
+endef
+endif # python3
+
+endif # __python3_host_mk_inc