python,python3: add Py[3]Shebang functions & move outside of script

Some packages just install some Python binaries, that may need their
shebang fixed.
This change adds some utilities to help with that and try to centralize the
sed rules a bit.

It also removes the logic from the `python-package-install.sh` into the
`python-package[3].mk` files. This does 2 things:
1. It minimizes the need for the shell script to know the Python
   version 2/3
2. Makes the logic re-usable in packages; especially if the install rules
   differ a bit

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

lang/python/python-package-install.sh

@@ -54,8 +54,6 @@ python="$4"
 mode="$5"
 filespec="$6"
 
-SED="${SED:-sed -e}"
-
 find "$src_dir" -name "*.exe" -delete
 
 process_filespec "$src_dir" "$dst_dir" "$filespec" || {
@@ -63,12 +61,6 @@ process_filespec "$src_dir" "$dst_dir" "$filespec" || {
 	exit 1
 }
 
-usr_bin_dir="$dst_dir/usr/bin"
-
-if [ -d "$usr_bin_dir" ] ; then
-	$SED "1"'!'"b;s,^#"'!'".*python.*,#"'!'"/usr/bin/python${ver}," -i --follow-symlinks $usr_bin_dir/*
-fi
-
 if [ "$mode" == "sources" ] ; then
 	# Copy only python source files
 	find "$dst_dir" -not -type d -not -name "*.py" -delete

lang/python/python-package.mk

@@ -35,6 +35,10 @@ ifdef CONFIG_USE_MIPS16
   TARGET_CFLAGS += -mno-mips16 -mno-interlink-mips16
 endif
 
+define PyShebang
+$(SED) "1"'!'"b;s,^#"'!'".*python.*,#"'!'"/usr/bin/python2," -i --follow-symlinks $(1)
+endef
+
 define PyPackage
 
   define Package/$(1)-src
@@ -74,11 +78,13 @@ define PyPackage
 
   define Package/$(1)/install
 	$$(call PyPackage/$(1)/install,$$(1))
-	SED="$(SED)" \
 	$(SHELL) $(python_mk_path)python-package-install.sh "2" \
 		"$(PKG_INSTALL_DIR)" "$$(1)" \
 		"$(HOST_PYTHON_BIN)" "$$(2)" \
-		"$$$$$$$$$$(call shvar,PyPackage/$(1)/filespec)"
+		"$$$$$$$$$$(call shvar,PyPackage/$(1)/filespec)" && \
+	if [ -d "$$(1)/usr/bin" ]; then \
+		$(call PyShebang,$$(1)/usr/bin/*) ; \
+	fi
   endef
 
   define Package/$(1)-src/install

lang/python/python3-package.mk

@@ -34,6 +34,10 @@ ifdef CONFIG_USE_MIPS16
   TARGET_CFLAGS += -mno-mips16 -mno-interlink-mips16
 endif
 
+define Py3Shebang
+$(SED) "1"'!'"b;s,^#"'!'".*python.*,#"'!'"/usr/bin/python3," -i --follow-symlinks $(1)
+endef
+
 define Py3Package
 
   define Package/$(1)-src
@@ -73,12 +77,14 @@ define Py3Package
 
   define Package/$(1)/install
 	$$(call Py3Package/$(1)/install,$$(1))
-	SED="$(SED)" \
 	$(SHELL) $(python3_mk_path)python-package-install.sh "3" \
 		"$(PKG_INSTALL_DIR)" "$$(1)" \
 		"$(HOST_PYTHON3_BIN)" "$$(2)" \
-		"$$$$$$$$$$(call shvar,Py3Package/$(1)/filespec)"
-  endef
+		"$$$$$$$$$$(call shvar,Py3Package/$(1)/filespec)" && \
+ 	if [ -d "$$(1)/usr/bin" ]; then \
+		$(call Py3Shebang,$$(1)/usr/bin/*) ; \
+	fi
+ endef
 
   define Package/$(1)-src/install
 	$$(call Package/$(1)/install,$$(1),sources)