Add a comment to clarify why there are two invocations of $(CC)
@@ -17,6 +17,7 @@ build/%.o: src/%.c
$(CC) $(COMMON_CFLAGS) -c $^ -o $@
build/libbuiltins.so: $(LIBBUILTINS_OBJS)
+ # -U is not supported by the GNU linker. Retry without this option if the first command fails.
$(CC) -Wl,-U,_lucet_vmctx_current_memory -Wl,-U,_lucet_vmctx_get_heap -shared $^ -o $@ 2> /dev/null || \
$(CC) -shared $^ -o $@
