fix minimal builds

Author: anwayde

src/discof/ipecho/Local.mk

@@ -1,3 +1,4 @@
+ifdef FD_HAS_ALLOCA
 $(call add-objs,fd_ipecho_tile,fd_discof)
 $(call add-objs,fd_ipecho_client,fd_discof)
 $(call add-objs,fd_ipecho_server,fd_discof)
@@ -7,3 +8,4 @@ $(call make-unit-test,test_ipecho_client,test_ipecho_client,fd_discof fd_disco f
 ifdef FD_HAS_HOSTED
 $(call make-fuzz-test,fuzz_ipecho_client,fuzz_ipecho_client,fd_discof fd_flamenco fd_ballet fd_util)
 endif
+endif