module: build hostprogs for each module

This fixes [BUGID #241]

The kernel hostprogs are built for the host architecture. They should not be
deployed to the target, and they should not be included in an sstate package
which might get reused on a host of a different architecture.

As we don't build many out-of-tree modules, this patch takes the approach of
building the hostprogs as part of the module compile process with a
do_compile_prepend() routine in module.bbclass.

We don't have to clean the hostprogs as modules depend on the kernel being
populate_staging, so its done with the staging directory by the time we run.

(From OE-Core rev: e807fc977770cb64a217768672c18437ea8f3057)

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Gary Thomas <gary@mlbassoc.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/module.bbclass

@@ -3,6 +3,13 @@ DEPENDS += "virtual/kernel"
 
 inherit module-base
 
+# Ensure the hostprogs are available for module compilation
+module_do_compile_prepend() {
+	unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS 
+	oe_runmake CC="${KERNEL_CC}" LD="${KERNEL_LD}" AR="${KERNEL_AR}" \
+	           -C ${STAGING_KERNEL_DIR} scripts
+}
+
 module_do_compile() {
 	unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
 	oe_runmake KERNEL_PATH=${STAGING_KERNEL_DIR}   \
@@ -15,7 +22,10 @@ module_do_compile() {
 
 module_do_install() {
 	unset CFLAGS CPPFLAGS CXXFLAGS LDFLAGS
-	oe_runmake DEPMOD=echo INSTALL_MOD_PATH="${D}" CC="${KERNEL_CC}" LD="${KERNEL_LD}" modules_install
+	oe_runmake DEPMOD=echo INSTALL_MOD_PATH="${D}" \
+	           KERNEL_SRC=${STAGING_KERNEL_DIR} \
+	           CC="${KERNEL_CC}" LD="${KERNEL_LD}" \
+	           modules_install
 }
 
 pkg_postinst_append () {