AM_CPPFLAGS = $(HAL_IO) $(STD_INCLUDES)
-STD_CFLAGS = -Wall -Werror-implicit-function-declaration -mxl-soft-div -msoft-float
+STD_CFLAGS = --std=gnu99 -Wall -Werror-implicit-function-declaration -mxl-soft-div -msoft-float
AM_CFLAGS = $(STD_CFLAGS) -mxl-soft-mul -mxl-barrel-shift
#AM_CFLAGS = $(STD_CFLAGS) -mxl-soft-mul -mxl-barrel-shift -mxl-gp-opt -G 16384