pkg-download.mk: support detection of URI schemes in DOWNLOAD

When using one of the package infrastructures, the DOWNLOAD function
uses $(PKG)_SITE_METHOD to determine the appropriate download method,
which is autodetected based on the URI if none was explicitly set.

When the DOWNLOAD function is called directly, for example when
downloading a toolchain, or from a package that does not use one of
the package infrastructures, the SITE_METHOD is not autodetected,
and thus the download defaults to wget.

This patch adds URI scheme detection directly to the DOWNLOAD method,
in case no SITE_METHOD was detected yet.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/pkg-download.mk

@@ -214,7 +214,12 @@ define DOWNLOAD_INNER
 		esac ; \
 	fi ; \
 	if test -n "$(1)" ; then \
-		case "$($(PKG)_SITE_METHOD)" in \
+		if test -z "$($(PKG)_SITE_METHOD)" ; then \
+			scheme="$(call geturischeme,$(1))" ; \
+		else \
+			scheme="$($(PKG)_SITE_METHOD)" ; \
+		fi ; \
+		case "$$scheme" in \
 			git) $($(DL_MODE)_GIT) && exit ;; \
 			svn) $($(DL_MODE)_SVN) && exit ;; \
 			bzr) $($(DL_MODE)_BZR) && exit ;; \