unix/Makefile: Add lib/mbedtls to GIT_SUBMODULES.
While the current default is axTLS, fully generic support (e.g. duplex,
non-blocking) requires mbedTLS.
@@ -16,7 +16,7 @@ UNAME_S := $(shell uname -s)
# include py core make definitions
include $(TOP)/py/py.mk
-GIT_SUBMODULES = lib/axtls lib/berkeley-db-1.xx lib/libffi
+GIT_SUBMODULES = lib/axtls lib/mbedtls lib/berkeley-db-1.xx lib/libffi
INC += -I.
INC += -I$(TOP)
