Demo/Posix_GCC: add demo application for Posix port using GCC

This is largely a copy of the Windows demo application with a few key
changes:

- heap_3 (use malloc()/free()) so tools like valgrind "just work".

- printf() wrapped in a mutex to prevent deadlocks on the internal
  pthread mutexes inside printf().

SCons (https://scons.org/) is used as the build system.

This will be built as a 64-bit application, but note that the memory
allocation trace points only record the lower 32-bits of the address.

FreeRTOS/Demo/Posix_GCC/src/FreeRTOSConfig.h

@@ -0,0 +1,158 @@
+/*
+ * FreeRTOS Kernel V10.3.0
+ * Copyright (C) 2020 Amazon.com, Inc. or its affiliates.  All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+#ifndef FREERTOS_CONFIG_H
+#define FREERTOS_CONFIG_H
+
+/*-----------------------------------------------------------
+ * Application specific definitions.
+ *
+ * These definitions should be adjusted for your particular hardware and
+ * application requirements.
+ *
+ * THESE PARAMETERS ARE DESCRIBED WITHIN THE 'CONFIGURATION' SECTION OF THE
+ * FreeRTOS API DOCUMENTATION AVAILABLE ON THE FreeRTOS.org WEB SITE.  See
+ * http://www.freertos.org/a00110.html
+ *----------------------------------------------------------*/
+
+#define configUSE_PREEMPTION					1
+#define configUSE_PORT_OPTIMISED_TASK_SELECTION	0
+#define configUSE_IDLE_HOOK						1
+#define configUSE_TICK_HOOK						1
+#define configUSE_DAEMON_TASK_STARTUP_HOOK		1
+#define configTICK_RATE_HZ						( 1000 ) /* In this non-real time simulated environment the tick frequency has to be at least a multiple of the Win32 tick frequency, and therefore very slow. */
+#define configMINIMAL_STACK_SIZE				( ( unsigned short ) 70 ) /* In this simulated case, the stack only has to hold one small structure as the real stack is part of the win32 thread. */
+#define configTOTAL_HEAP_SIZE					( ( size_t ) ( 65 * 1024 ) )
+#define configMAX_TASK_NAME_LEN					( 12 )
+#define configUSE_TRACE_FACILITY				1
+#define configUSE_16_BIT_TICKS					0
+#define configIDLE_SHOULD_YIELD					1
+#define configUSE_MUTEXES						1
+#define configCHECK_FOR_STACK_OVERFLOW			0
+#define configUSE_RECURSIVE_MUTEXES				1
+#define configQUEUE_REGISTRY_SIZE				20
+#define configUSE_APPLICATION_TASK_TAG			1
+#define configUSE_COUNTING_SEMAPHORES			1
+#define configUSE_ALTERNATIVE_API				0
+#define configUSE_QUEUE_SETS					1
+#define configUSE_TASK_NOTIFICATIONS			1
+#define configSUPPORT_STATIC_ALLOCATION			1
+
+/* Software timer related configuration options.  The maximum possible task
+priority is configMAX_PRIORITIES - 1.  The priority of the timer task is
+deliberately set higher to ensure it is correctly capped back to
+configMAX_PRIORITIES - 1. */
+#define configUSE_TIMERS						1
+#define configTIMER_TASK_PRIORITY				( configMAX_PRIORITIES - 1 )
+#define configTIMER_QUEUE_LENGTH				20
+#define configTIMER_TASK_STACK_DEPTH			( configMINIMAL_STACK_SIZE * 2 )
+
+#define configMAX_PRIORITIES					( 7 )
+
+/* Run time stats gathering configuration options. */
+unsigned long ulGetRunTimeCounterValue( void ); /* Prototype of function that returns run time counter. */
+void vConfigureTimerForRunTimeStats( void );	/* Prototype of function that initialises the run time counter. */
+#define configGENERATE_RUN_TIME_STATS			1
+
+/* Co-routine related configuration options. */
+#define configUSE_CO_ROUTINES 					0
+#define configMAX_CO_ROUTINE_PRIORITIES			( 2 )
+
+/* This demo can use of one or more example stats formatting functions.  These
+format the raw data provided by the uxTaskGetSystemState() function in to human
+readable ASCII form.  See the notes in the implementation of vTaskList() within
+FreeRTOS/Source/tasks.c for limitations. */
+#define configUSE_STATS_FORMATTING_FUNCTIONS	0
+
+/* Enables the test whereby a stack larger than the total heap size is
+requested. */
+#define configSTACK_DEPTH_TYPE uint32_t
+
+/* Set the following definitions to 1 to include the API function, or zero
+to exclude the API function.  In most cases the linker will remove unused
+functions anyway. */
+#define INCLUDE_vTaskPrioritySet				1
+#define INCLUDE_uxTaskPriorityGet				1
+#define INCLUDE_vTaskDelete						1
+#define INCLUDE_vTaskCleanUpResources			0
+#define INCLUDE_vTaskSuspend					1
+#define INCLUDE_vTaskDelayUntil					1
+#define INCLUDE_vTaskDelay						1
+#define INCLUDE_uxTaskGetStackHighWaterMark		1
+#define INCLUDE_uxTaskGetStackHighWaterMark2	1
+#define INCLUDE_xTaskGetSchedulerState			1
+#define INCLUDE_xTimerGetTimerDaemonTaskHandle	1
+#define INCLUDE_xTaskGetIdleTaskHandle			1
+#define INCLUDE_xTaskGetHandle					1
+#define INCLUDE_eTaskGetState					1
+#define INCLUDE_xSemaphoreGetMutexHolder		1
+#define INCLUDE_xTimerPendFunctionCall			1
+#define INCLUDE_xTaskAbortDelay					1
+
+#define configINCLUDE_MESSAGE_BUFFER_AMP_DEMO	0
+#if ( configINCLUDE_MESSAGE_BUFFER_AMP_DEMO == 1 )
+	extern void vGenerateCoreBInterrupt( void * xUpdatedMessageBuffer );
+	#define sbSEND_COMPLETED( pxStreamBuffer ) vGenerateCoreBInterrupt( pxStreamBuffer )
+#endif /* configINCLUDE_MESSAGE_BUFFER_AMP_DEMO */
+
+extern void vAssertCalled( unsigned long ulLine, const char * const pcFileName );
+
+/* projCOVERAGE_TEST should be defined on the command line so this file can be
+used with multiple project configurations.  If it is
+ */
+#ifndef projCOVERAGE_TEST
+	#error projCOVERAGE_TEST should be defined to 1 or 0 on the command line.
+#endif
+
+#if( projCOVERAGE_TEST == 1 )
+	/* Insert NOPs in empty decision paths to ensure both true and false paths
+	are being tested. */
+	#define mtCOVERAGE_TEST_MARKER() __asm volatile( "NOP" )
+
+	/* Ensure the tick count overflows during the coverage test. */
+	#define configINITIAL_TICK_COUNT 0xffffd800UL
+
+	/* Allows tests of trying to allocate more than the heap has free. */
+	#define configUSE_MALLOC_FAILED_HOOK			0
+
+	/* To test builds that remove the static qualifier for debug builds. */
+	#define portREMOVE_STATIC_QUALIFIER
+#else
+	/* It is a good idea to define configASSERT() while developing.  configASSERT()
+	uses the same semantics as the standard C assert() macro.  Don't define
+	configASSERT() when performing code coverage tests though, as it is not
+	intended to asserts() to fail, some some code is intended not to run if no
+	errors are present. */
+	#define configASSERT( x ) if( ( x ) == 0 ) vAssertCalled( __LINE__, __FILE__ )
+
+	#define configUSE_MALLOC_FAILED_HOOK			1
+
+	/* Include the FreeRTOS+Trace FreeRTOS trace macro definitions. */
+	#include "trcRecorder.h"
+#endif
+
+
+#endif /* FREERTOS_CONFIG_H */