unix: Add btstack to the unix submodules list.

But only when bluetooth is enabled, i.e. if building the dev or coverage
variants, and we have libusb available.

Update travis to match, i.e. specify the variant when doing
`make submodules`.

.travis.yml

@@ -52,6 +52,7 @@ jobs:
         # OSX has poor time resolution and the following tests do not have the correct output
         - (cd tests && ./run-tests --exclude 'uasyncio_(basic|heaplock|lock|wait_task)')
         # check for additional compiler errors/warnings
+        - make ${MAKEOPTS} -C ports/unix VARIANT=coverage submodules
         - make ${MAKEOPTS} -C ports/unix VARIANT=coverage
       after_failure:
         - tests/run-tests --print-failures
@@ -108,8 +109,8 @@ jobs:
         - python3 --version
       script:
         - make ${MAKEOPTS} -C mpy-cross
-        - make ${MAKEOPTS} -C ports/unix submodules
-        - make ${MAKEOPTS} -C ports/unix deplibs
+        - make ${MAKEOPTS} -C ports/unix VARIANT=coverage submodules
+        - make ${MAKEOPTS} -C ports/unix VARIANT=coverage deplibs
         - make ${MAKEOPTS} -C ports/unix VARIANT=coverage
         # run the main test suite
         - make -C ports/unix VARIANT=coverage test_full
@@ -143,8 +144,8 @@ jobs:
         - python3 --version
       script:
         - make ${MAKEOPTS} -C mpy-cross
-        - make ${MAKEOPTS} -C ports/unix MICROPY_FORCE_32BIT=1 submodules
-        - make ${MAKEOPTS} -C ports/unix MICROPY_FORCE_32BIT=1 deplibs
+        - make ${MAKEOPTS} -C ports/unix MICROPY_FORCE_32BIT=1 VARIANT=coverage submodules
+        - make ${MAKEOPTS} -C ports/unix MICROPY_FORCE_32BIT=1 VARIANT=coverage deplibs
         - make ${MAKEOPTS} -C ports/unix MICROPY_FORCE_32BIT=1 VARIANT=coverage
         # run the main test suite
         - make -C ports/unix MICROPY_FORCE_32BIT=1 VARIANT=coverage test_full || travis_terminate 1
@@ -183,8 +184,8 @@ jobs:
         - sudo apt-get install gcc-multilib libffi-dev:i386
       script:
         - make ${MAKEOPTS} -C mpy-cross PYTHON=python2
-        - make ${MAKEOPTS} -C ports/unix submodules
-        - make ${MAKEOPTS} -C ports/unix PYTHON=python2 deplibs
+        - make ${MAKEOPTS} -C ports/unix VARIANT=nanbox submodules
+        - make ${MAKEOPTS} -C ports/unix PYTHON=python2 VARIANT=nanbox deplibs
         - make ${MAKEOPTS} -C ports/unix PYTHON=python2 VARIANT=nanbox
         - make ${MAKEOPTS} -C ports/unix PYTHON=python2 VARIANT=nanbox test_full || travis_terminate 1
         - make ${MAKEOPTS} -C ports/unix clean

extmod/btstack/btstack.mk

@@ -14,6 +14,8 @@ CFLAGS_MOD += -DMICROPY_BLUETOOTH_BTSTACK=1
 
 BTSTACK_DIR = $(TOP)/lib/btstack
 
+ifneq ($(wildcard $(BTSTACK_DIR)/src),)
+
 include $(BTSTACK_DIR)/src/Makefile.inc
 include $(BTSTACK_DIR)/src/ble/Makefile.inc
 
@@ -52,3 +54,4 @@ endif
 $(BUILD)/lib/btstack/src/%.o: CFLAGS += $(BTSTACK_WARNING_CFLAGS)
 
 endif
+endif

ports/unix/Makefile

@@ -31,7 +31,7 @@ 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/berkeley-db-1.xx lib/libffi
 
 INC +=  -I.
 INC +=  -I$(TOP)
@@ -146,6 +146,8 @@ MICROPY_BLUETOOTH_BTSTACK ?= 1
 MICROPY_BLUETOOTH_BTSTACK_USB ?= 1
 
 ifeq ($(MICROPY_BLUETOOTH_BTSTACK),1)
+GIT_SUBMODULES += lib/btstack
+
 include $(TOP)/extmod/btstack/btstack.mk
 endif