local_includes += -Ibindings/cxx/include -I$(srcdir)/bindings/cxx/include -Ibindings/cxx
endif
# Ensure that local include directories are always searched first.
-AM_CPPFLAGS = $(local_includes) -D_DEFAULT_SOURCE -DFIRMWARE_DIR='"$(FIRMWARE_DIR)"'
+AM_CPPFLAGS = $(local_includes) -D_POSIX_C_SOURCE=200112L -DFIRMWARE_DIR='"$(FIRMWARE_DIR)"'
# The tests CFLAGS are a superset of the libsigrok CFLAGS, and the
# python bindings CFLAGS are a superset of the C++ bindings CFLAGS.