Add a new module implementing a queue data structure.

Since the functions are simple make them inline functions. This provides a
small code size saving.

tests/app_queue_test/Makefile

@@ -0,0 +1,32 @@
+# The TARGET variable determines what target system the application is
+# compiled for. It either refers to an XN file in the source directories
+# or a valid argument for the --target option when compiling
+TARGET = XP-SKC-SU1
+
+# The APP_NAME variable determines the name of the final .xe file. It should
+# not include the .xe postfix. If left blank the name will default to
+# the project name
+APP_NAME = app_queue_test
+
+# The USED_MODULES variable lists other module used by the application.
+USED_MODULES = module_queue
+
+# The flags passed to xcc when building the application
+# You can also set the following to override flags for a particular language:
+# XCC_XC_FLAGS, XCC_C_FLAGS, XCC_ASM_FLAGS, XCC_CPP_FLAGS
+# If the variable XCC_MAP_FLAGS is set it overrides the flags passed to
+# xcc for the final link (mapping) stage.
+XCC_FLAGS = -O0 -g
+
+# The VERBOSE variable, if set to 1, enables verbose output from the make system.
+VERBOSE = 0
+
+# This change to the module path is so that this application can be in the
+# tests sub-directory in it's git repo
+ifeq ($(notdir $(abspath ..)),tests)
+PATHSEP = $(if $(findstring Windows, $(OS))$(findstring WINDOWS,$(OS)),;,:)
+XMOS_MODULE_PATH := $(XMOS_MODULE_PATH)$(PATHSEP)../../..
+endif
+
+XMOS_MAKE_PATH ?= ../..
+-include $(XMOS_MAKE_PATH)/xcommon/module_xcommon/build/Makefile.common