zvbi fails to build on i386: error: ‘__BYTE_ORDER__’ undeclared (first use in this function)

[barracuda156]

/usr/bin/gcc-4.2 -std=gnu99 -DHAVE_CONFIG_H -I. -I..  -I..  -D_REENTRANT -D_GNU_SOURCE -I/opt/local/include -I..  -D_REENTRANT -D_GNU_SOURCE -pipe -Os -arch i386 -MT caption.o -MD -MP -MF .deps/caption.Tpo -c -o caption.o caption.c
caption.c: In function ‘draw_transparent_spaces’:
caption.c:217: error: ‘__BYTE_ORDER__’ undeclared (first use in this function)
caption.c:217: error: (Each undeclared identifier is reported only once
caption.c:217: error: for each function it appears in.)
caption.c:217: error: ‘__ORDER_BIG_ENDIAN__’ undeclared (first use in this function)
make[2]: *** [caption.o] Error 1
make[2]: *** Waiting for unfinished jobs....
mv -f .deps/unicode.Tpo .deps/unicode.Po
make[2]: Leaving directory `/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_macports_release_tarballs_ports_multimedia_zvbi/zvbi/work/zvbi-0.2.35/test'
make[1]: *** [all-recursive] Error 1

This is caption.c from tests. The code has:

	case 24: /* assumed to be B G R in memory */
		d = ximgdata + column * CELL_WIDTH * 3
			+ row * CELL_HEIGHT * TEXT_WIDTH * 3;

		s = (const uint8_t *) &video_xcolor.pixel;
		if (Z_BYTE_ORDER == Z_BIG_ENDIAN)
			s += sizeof (video_xcolor.pixel) - 3;

		for (j = 0; j < CELL_HEIGHT; ++j) {
			for (i = 0; i < n_columns * CELL_WIDTH; ++i)
				memcpy (d + i * 3, s, 3);

			d += TEXT_WIDTH * 3;
		}

		break;

[ryandesign (Ryan Carsten Schmidt)]

Duplicate of #68520.