jtag: linuxgpiod: add macro HAVE_LIBGPIOD_V1

To prepare the support for libgpiod v2, add a macro to report the
old version v1 of the library.

Extracted part of 8226: jtag: linuxgpiod:
finalize emulation of libgpiod v2 API for older versions

Link: https://review.openocd.org/c/openocd/+/8226
Change-Id: Ib9c4e495b326770fabadbc752df8aa0a920b1831
Signed-off-by: Michael Heimpold <[email protected]>
Signed-off-by: Tomas Vanek <[email protected]>
Signed-off-by: Antonio Borneo <[email protected]>
Reviewed-on: https://review.openocd.org/c/openocd/+/9118
Tested-by: jenkins

Author: mhei

configure.ac

@@ -585,6 +585,7 @@ PKG_CHECK_MODULES([LIBFTDI], [libftdi1], [
 
 PKG_CHECK_MODULES([LIBGPIOD], [libgpiod < 2.0], [
 	use_libgpiod=yes
+	AC_DEFINE([HAVE_LIBGPIOD_V1], [1], [define if libgpiod is version v1.x])
 	PKG_CHECK_EXISTS([libgpiod >= 1.5],
 		[AC_DEFINE([HAVE_LIBGPIOD1_FLAGS_BIAS], [1], [define if libgpiod v1 has line request flags bias])])
 ], [use_libgpiod=no])