diff --git a/Makefile b/Makefile
index c6fec6af8..1d3fe26a9 100644
--- a/Makefile
+++ b/Makefile
@@ -514,7 +514,11 @@ ignore_implicit = $(if $(subst environment,,$(origin $(1))),         \
 # is used to report a list of all flags which were used to build this version.
 # Do not assign anything to it.
 BUILD_OPTIONS  := $(foreach opt,$(use_opts),$(call ignore_implicit,$(opt)))
-BUILD_FEATURES := $(foreach opt,$(patsubst USE_%,%,$(use_opts)),$(if $(USE_$(opt)),+$(opt),-$(opt)))
+
+# Make a list of all known features with +/- prepended depending on their
+# activation status. Must be a macro so that dynamically enabled ones are
+# evaluated with their current status.
+BUILD_FEATURES  = $(foreach opt,$(patsubst USE_%,%,$(use_opts)),$(if $(USE_$(opt)),+$(opt),-$(opt)))
 
 # All USE_* options have their equivalent macro defined in the code (some might
 # possibly be unused though)