pass $MAKE_PARAM to the actual build process, too

Otherwise setting VERBOSE=1 would have no effect on the build process on
its own.

build.sh

@@ -175,12 +175,12 @@ for target in ${TARGETS} ; do
     # now we can start building the images for the target platform
     progress "Building FFPB-flavoured Gluon firmware for target ${target}. You'd better go and fetch some c0ffee!"
     make_targets="prepare"
-    eval "${gluon_build_env_vars} faketime \"$BUILD_TS\" make -j ${MAKEJOBS} ${make_targets}"
+    eval "${gluon_build_env_vars} faketime \"$BUILD_TS\" make -j ${MAKEJOBS} ${make_targets}${MAKE_PARAM}"
     [ "$?" -eq "0" ] || abort "Failed to build firmware for target-platform ${target}."
 
     # finally compile the firmware binaries
     progress "Compiling binary firmware images."
-    faketime "$BUILD_TS" make images
+    faketime "$BUILD_TS" make images${MAKE_PARAM}
     [ "$?" -eq "0" ] || abort "Failed to assemble images for target-platform ${target}."
 done