diff --git a/Makefile b/Makefile
index 3cc51bd07e182a353b1fe6bd1d5a699c422a7032..9c7ef99328ec66f9e6653dd6baea923f653dea1d 100644
--- a/Makefile
+++ b/Makefile
@@ -100,6 +100,10 @@ install_vars = DESTDIR=$(firstword $(wildcard $(CURDIR)/packages/*/build)) prefi
 CFLAGS =
 export CFLAGS
 
+# For the light build only, you can add externals to be included in the build.
+addons =
+export addons
+
 # You can also set this variable to specify externals NOT to be built. E.g.,
 # to prevent building Gem (which takes an eternity to build): blacklist = gem
 blacklist =
diff --git a/externals/Makefile b/externals/Makefile
index 95c5b7f40780a675e7096080c4cc14e0f02add10..edecfa593b282ec8aab3387d8d0559f9b9e1da1e 100644
--- a/externals/Makefile
+++ b/externals/Makefile
@@ -141,6 +141,8 @@ CXXFLAGS = $(CFLAGS)
 ifeq ($(LIGHT),yes)
 # minimal set of extensions for the "light" build
 lib_targets = loaders-libdir pddp
+# add specified externals to the light build
+lib_targets += $(addons)
 INCREMENTAL = yes
 else
 lib_targets = adaptive arraysize autotune bassemu bendinfix boids bsaylor comport creb cxc cyclone disis earplug ekext ext13 fftease flatgui fluid freeverb ggee hcs iem_ambi iem_bin_ambi iemlib iemgui iemguts iem_adaptfilt iemmatrix iemxmlrpc iem_delay iem_roomsim iem_spec2 iem_tab jasch_lib loaders-libdir lyonpotpourri mapping markex maxlib mjlib moocow moonlib motex mrpeach oscx pan pdcontainer pddp pdlua pdogg plugin pmpd rjlib sigpack smlib tof unauthorized vbap windowing zexy