From f15f4fb76fc83f5176f17fbfce05cb5b761a2fac Mon Sep 17 00:00:00 2001
From: Russ Butler <russ.butler@arm.com>
Date: Sun, 12 Jun 2016 01:10:57 +0100
Subject: [PATCH] Only allow one thread on unsafe standard libs

When using a standard library which does not support multi-threading
allow only one thread to be used.  This allows the code to remain
safe.

This also pulls up on the mbed library to use this change:
https://github.com/mbedmicro/mbed/compare/df0c855df97688074545693f66bcca5cf9f42111...5acdad9fd7b334a5a2fbe2f927f0a091ae0a914e
---
 mbed.lib                |  2 +-
 tools/toolchains/arm.py |  4 ++++
 tools/toolchains/gcc.py | 16 +++++++++++++++-
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/mbed.lib b/mbed.lib
index 5d4b3928f6..ff0438e019 100644
--- a/mbed.lib
+++ b/mbed.lib
@@ -1 +1 @@
-https://github.com/mbedmicro/mbed/#df0c855df97688074545693f66bcca5cf9f42111
+https://github.com/mbedmicro/mbed/#5acdad9fd7b334a5a2fbe2f927f0a091ae0a914e
diff --git a/tools/toolchains/arm.py b/tools/toolchains/arm.py
index 5be4487c4b..11b6564dfa 100644
--- a/tools/toolchains/arm.py
+++ b/tools/toolchains/arm.py
@@ -242,6 +242,10 @@ class ARM_MICRO(ARM):
         self.cppc += ["-D__MICROLIB", "--library_type=microlib"]
         self.ld   += ["--library_type=microlib"]
 
+        # Only allow a single thread
+        self.cc += ["-DMBED_RTOS_SINGLE_THREAD"]
+        self.cppc += ["-DMBED_RTOS_SINGLE_THREAD"]
+
         # We had to patch microlib to add C++ support
         # In later releases this patch should have entered mainline
         if ARM_MICRO.PATCHED_LIBRARY:
diff --git a/tools/toolchains/gcc.py b/tools/toolchains/gcc.py
index 2dfc03e24a..aa71e1360e 100644
--- a/tools/toolchains/gcc.py
+++ b/tools/toolchains/gcc.py
@@ -252,8 +252,22 @@ class GCC_ARM(GCC):
         GCC.__init__(self, target, options, notify, macros, silent, GCC_ARM_PATH, extra_verbose=extra_verbose)
 
         # Use latest gcc nanolib
-        if "thread-safe" not in self.options:
+        if "big-build" in self.options:
+            use_nano = False
+        elif "small-build" in self.options:
+            use_nano = True
+        elif target.default_build == "standard":
+            use_nano = False
+        elif target.default_build == "small":
+            use_nano = True
+        else:
+            use_nano = False
+
+        if use_nano:
             self.ld.append("--specs=nano.specs")
+            self.cc += ["-DMBED_RTOS_SINGLE_THREAD"]
+            self.cppc += ["-DMBED_RTOS_SINGLE_THREAD"]
+
         if target.name in ["LPC1768", "LPC4088", "LPC4088_DM", "LPC4330", "UBLOX_C027", "LPC2368"]:
             self.ld.extend(["-u _printf_float", "-u _scanf_float"])
         elif target.name in ["RZ_A1H", "VK_RZ_A1H", "ARCH_MAX", "DISCO_F407VG", "DISCO_F429ZI", "DISCO_F469NI", "NUCLEO_F401RE", "NUCLEO_F410RB", "NUCLEO_F411RE", "NUCLEO_F446RE", "ELMO_F411RE", "MTS_MDOT_F411RE", "MTS_DRAGONFLY_F411RE", "DISCO_F746NG"]: