disable gpio cable driver when pread() is not available (i.e. Windows)

git-svn-id: https://urjtag.svn.sourceforge.net/svnroot/urjtag/trunk@1862 b68d4a1b-bc3d-0410-92ed-d4ac073336b7

urjtag/ChangeLog

@@ -1,3 +1,8 @@
+2010-10-09  Mike Frysinger  <vapier@gentoo.org>
+
+  * configure.ac: Check for pread availability and disable gpio cable driver
+    when not found (for Windows systems).
+
 2010-09-28  Mike Frysinger  <vapier@gentoo.org>
 
   * src/flash/amd_flash.c (urj_flash_amd_detect): Move the bus address range

urjtag/configure.ac

@@ -121,6 +121,7 @@ AC_CHECK_FUNCS(m4_flatten([
 	geteuid
 	getuid
 	nanosleep
+	pread
 	swprintf
 	usleep
 ]))
@@ -639,6 +640,9 @@ URJ_DRIVER_SET([cable], [
 			-e s/vsllink// \
 			-e s/xpc//`
 	])
+	AS_IF([test "x$ac_cv_func_pread" != "xyes"], [
+		drivers=`echo ${drivers} | $SED -e s/gpio//`
+	])
 ])
 dnl the "fake" jim cable driver is special
 AS_IF([echo "$enabled_cable_drivers" | $GREP -q jim], [