Merge tag 'v1.9.1'2.0.0-alpha.0

Fixes for stmhal USB mass storage, lwIP bindings and VFS regressions

This release provides an important fix for the USB mass storage device in
the stmhal port by implementing the SCSI SYNCHRONIZE_CACHE command, which
is now require by some Operating Systems.  There are also fixes for the
lwIP bindings to improve non-blocking sockets and error codes.  The VFS has
some regressions fixed including the ability to statvfs the root.

All changes are listed below.

py core:
- modbuiltins: add core-provided version of input() function
- objstr: catch case of negative "maxsplit" arg to str.rsplit()
- persistentcode: allow to compile with complex numbers disabled
- objstr: allow to compile with obj-repr D, and unicode disabled
- modsys: allow to compile with obj-repr D and PY_ATTRTUPLE disabled
- provide mp_decode_uint_skip() to help reduce stack usage
- makeqstrdefs.py: make script run correctly with Python 2.6
- objstringio: if created from immutable object, follow copy on write policy

extmod:
- modlwip: connect: for non-blocking mode, return EINPROGRESS
- modlwip: fix error codes for duplicate calls to connect()
- modlwip: accept: fix error code for non-blocking mode
- vfs: allow to statvfs the root directory
- vfs: allow "buffering" and "encoding" args to VFS's open()
- modframebuf: fix signed/unsigned comparison pendantic warning

lib:
- libm: use isfinite instead of finitef, for C99 compatibility
- utils/interrupt_char: remove support for KBD_EXCEPTION disabled

tests:
- basics/string_rsplit: add tests for negative "maxsplit" argument
- float: convert "sys.exit()" to "raise SystemExit"
- float/builtin_float_minmax: PEP8 fixes
- basics: convert "sys.exit()" to "raise SystemExit"
- convert remaining "sys.exit()" to "raise SystemExit"

unix port:
- convert to use core-provided version of built-in import()
- Makefile: replace references to make with $(MAKE)

windows port:
- convert to use core-provided version of built-in import()

qemu-arm port:
- Makefile: adjust object-file lists to get correct dependencies
- enable micropython.mem_*() functions to allow more tests

stmhal port:
- boards: enable DAC for NUCLEO_F767ZI board
- add support for NUCLEO_F446RE board
- pass USB handler as parameter to allow more than one USB handler
- usb: use local USB handler variable in Start-of-Frame handler
- usb: make state for USB device private to top-level USB driver
- usbdev: for MSC implement SCSI SYNCHRONIZE_CACHE command
- convert from using stmhal's input() to core provided version

cc3200 port:
- convert from using stmhal's input() to core provided version

teensy port:
- convert from using stmhal's input() to core provided version

esp8266 port:
- Makefile: replace references to make with $(MAKE)
- Makefile: add clean-modules target
- convert from using stmhal's input() to core provided version

zephyr port:
- modusocket: getaddrinfo: Fix mp_obj_len() usage
- define MICROPY_PY_SYS_PLATFORM (to "zephyr")
- machine_pin: use native Zephyr types for Zephyr API calls

docs:
- machine.Pin: remove out_value() method
- machine.Pin: add on() and off() methods
- esp8266: consistently replace Pin.high/low methods with .on/off
- esp8266/quickref: polish Pin.on()/off() examples
- network: move confusingly-named cc3200 Server class to its reference
- uos: deconditionalize, remove minor port-specific details
- uos: move cc3200 port legacy VFS mounting functions to its ref doc
- machine: sort machine classes in logical order, not alphabetically
- network: first step to describe standard network class interface

examples:
- embedding: use core-provided KeyboardInterrupt object

7 files changed, 44 insertions, 6 deletions

diff --git a/tests/thread/stress_aes.py b/tests/thread/stress_aes.py
index ecc963c92..df75e616c 100644
--- a/tests/thread/stress_aes.py
+++ b/tests/thread/stress_aes.py
@@ -8,7 +8,7 @@
 #
 # The AES code comes first (code originates from a C version authored by D.P.George)
 # and then the test harness at the bottom.  It can be tuned to be more/less
-# agressive by changing the amount of data to encrypt, the number of loops and
+# aggressive by changing the amount of data to encrypt, the number of loops and
 # the number of threads.
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
diff --git a/tests/thread/stress_create.py b/tests/thread/stress_create.py
new file mode 100644
index 000000000..2399746cc
--- /dev/null
+++ b/tests/thread/stress_create.py
@@ -0,0 +1,22 @@
+# stress test for creating many threads
+
+try:
+    import utime as time
+except ImportError:
+    import time
+import _thread
+
+def thread_entry(n):
+    pass
+
+thread_num = 0
+while thread_num < 500:
+    try:
+        _thread.start_new_thread(thread_entry, (thread_num,))
+        thread_num += 1
+    except MemoryError:
+        pass
+
+# wait for the last threads to terminate
+time.sleep(1)
+print('done')
diff --git a/tests/thread/stress_heap.py b/tests/thread/stress_heap.py
index ac3ebe049..5482a9ac6 100644
--- a/tests/thread/stress_heap.py
+++ b/tests/thread/stress_heap.py
@@ -3,6 +3,10 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+try:
+    import utime as time
+except ImportError:
+    import time
 import _thread
 
 def last(l):
@@ -37,6 +41,6 @@ n_finished = 0
 for i in range(n_thread):
     _thread.start_new_thread(thread_entry, (10000,))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(1)
diff --git a/tests/thread/thread_exc2.py.exp b/tests/thread/thread_exc2.py.exp
index 584bfab4d..cc7a20aa2 100644
--- a/tests/thread/thread_exc2.py.exp
+++ b/tests/thread/thread_exc2.py.exp
@@ -1,5 +1,5 @@
 Unhandled exception in thread started by <function thread_entry at 0x\[0-9a-f\]\+>
 Traceback (most recent call last):
-  File "thread/thread_exc2.py", line 6, in thread_entry
+  File \.\+, line 6, in thread_entry
 ValueError: 
 done
diff --git a/tests/thread/thread_lock4.py b/tests/thread/thread_lock4.py
index d77aa24ee..2f9d42d6b 100644
--- a/tests/thread/thread_lock4.py
+++ b/tests/thread/thread_lock4.py
@@ -2,6 +2,10 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+try:
+    import utime as time
+except ImportError:
+    import time
 import _thread
 
 def fac(n):
@@ -39,6 +43,7 @@ while True:
     with jobs_lock:
         if len(output) == n_jobs:
             break
+    time.sleep(1)
 
 # sort and print the results
 output.sort(key=lambda x: x[0])
diff --git a/tests/thread/thread_qstr1.py b/tests/thread/thread_qstr1.py
index c0256316e..f4136d964 100644
--- a/tests/thread/thread_qstr1.py
+++ b/tests/thread/thread_qstr1.py
@@ -2,6 +2,10 @@
 #
 # MIT license; Copyright (c) 2016 Damien P. George on behalf of Pycom Ltd
 
+try:
+    import utime as time
+except ImportError:
+    import time
 import _thread
 
 # function to check the interned string
@@ -28,8 +32,8 @@ n_qstr_per_thread = 100 # make 1000 for a more stressful test (uses more heap)
 for i in range(n_thread):
     _thread.start_new_thread(th, (i * n_qstr_per_thread, n_qstr_per_thread))
 
-# busy wait for threads to finish
+# wait for threads to finish
 while n_finished < n_thread:
-    pass
+    time.sleep(1)
 
 print('pass')
diff --git a/tests/thread/thread_stacksize1.py b/tests/thread/thread_stacksize1.py
index e62899631..62b6e5e40 100644
--- a/tests/thread/thread_stacksize1.py
+++ b/tests/thread/thread_stacksize1.py
@@ -38,6 +38,9 @@ _thread.stack_size(sz)
 for i in range(n_thread):
     _thread.start_new_thread(thread_entry, ())
 
+# reset stack size to default (for subsequent scripts on baremetal)
+_thread.stack_size()
+
 # busy wait for threads to finish
 while n_finished < n_thread:
     pass