## Small Functions ##
get_csrcs = $(foreach subdir, $(1), $(wildcard $(subdir)/*.c $(subdir)/*.C))
get_asmsrcs = $(foreach subdir, $(1), $(wildcard $(subdir)/*.s $(subdir)/*.S))
get_cxxsrcs = $(foreach subdir, $(1), $(wildcard $(subdir)/*.cpp $(subdir)/*.CPP $(subdir)/*.cc $(subdir)/*.CC))
check_item_exist = $(strip $(if $(filter 1, $(words $(1))),$(filter $(1), $(sort $(2))),))

###
# For Windows, in Win9x, COMSPEC is defined, WinNT, ComSpec is defined
###
ifdef ComSpec
	WINCMD:=$(ComSpec)
endif
ifdef COMSPEC
	WINCMD:=$(COMSPEC)
endif

ifneq "$(WINCMD)" ""
ifneq "$(findstring /cygdrive/,$(PATH))" ""
	HOST_OS:=Cygwin
else
	HOST_OS:=Windows
endif
else
	HOST_OS:=$(shell uname)
endif

##
# Define one space
##
nullstring=
space=$(nullstring) # one space

RM=rm -rf
RMD=rm -rf
ECHO=echo
# TODO cp currently only avail in linux
# windows build tool not provide it
CP=cp -rf
# https://github.com/bmatzelle/gow/issues/171#issuecomment-91709839
# add extra "" around mkdir to overwrite cmd default mkdir in windows
MKD="mkdir" -p
PS=/$(nullstring)
NULL=/dev/null

## Check OS ##
## Check OS == Windows ##
ifeq "$(HOST_OS)" "Windows"
	PS=\$(nullstring)
	NULL=NUL
	DOS_CMD=$(WINCMD) /C
	# when OS is windows, force SHELL to be cmd
	# or if in your evironment path there is
	# a mingw shell, the make process will go wrong
	SHELL:=$(WINCMD)
endif

## Check OS == Linux ##
ifeq "$(HOST_OS)" "Linux"
	PS=/$(nullstring)
	NULL=/dev/null
endif

## Check OS == Darwin ##
ifeq "$(HOST_OS)" "Darwin"
	PS=/$(nullstring)
	NULL=/dev/null
endif

## MAKEFILE COMPILE MESSAGE CONTROL ##
ifeq ($(V),1)
	Q=
else
	Q=@
endif

## Suppress All Message ##
ifeq ($(SILENT), 1)
	TRACE_CREATE_DIR    =
	TRACE_COMPILE       =
	TRACE_ASSEMBLE      =
	TRACE_LINK          =
	TRACE_ARCHIVE       =
	## Overwrite Q Value set by V option ##
	override Q=@
else
	TRACE_CREATE_DIR    = @$(ECHO) "Creating Directory : " $(@D)
	TRACE_COMPILE       = @$(ECHO) "Compiling  : " $<
	TRACE_ASSEMBLE      = @$(ECHO) "Assembling : " $<
	TRACE_LINK          = @$(ECHO) "Linking    : " $@
	TRACE_ARCHIVE       = @$(ECHO) "Archiving  : " $@
endif