Fix calling of depmod

"depmod -e" needs either -F System.map or -E Module.symvers
"depmod -b" resolvs an empty argument to PWD, so only use -b if
INSTALL_MOD_PATH is actually set

gen_compile.sh

@@ -302,7 +302,12 @@ compile_modules() {
 	[ "${INSTALL_MOD_PATH}" != '' ] && export INSTALL_MOD_PATH
 	MAKEOPTS="${MAKEOPTS} -j1" compile_generic "modules_install" kernel
 	print_info 1 "        >> Generating module dependency data..."
-	depmod -a -e -b "${INSTALL_MOD_PATH}"/lib/modules/$KV ${KV}
+	if [ "${INSTALL_MOD_PATH}" != '' ]
+	then
+		depmod -a -e -F "${KERNEL_OUTPUTDIR}"/System.map -b "${INSTALL_MOD_PATH}" ${KV}
+	else
+		depmod -a -e -F "${KERNEL_OUTPUTDIR}"/System.map ${KV}
+	fi
 	unset UNAME_MACHINE
 }