package/autoconf: disable gtkdocize integration

Since version 2.70 (which was skipped when bumping to 2.71 in ecd54b65c1)
autoreconf checks if a package uses gtkdoc by check if the macro GTK_DOC_CHECK
is used. If detected, gtkdocize will be run as part of the reconfiguration
process.

http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commit;h=dd880a0a6de5602cdd40b770ed6b083b34aa0768

If gtkdocize is not installed, this fails with:

Can't exec "gtkdocize": No such file or directory at /home/buildroot/autobuild/instance-1/output-1/host/share/autoconf/Autom4te/FileUtils.pm line 293.
autoreconf: error: gtkdocize failed with exit status: 2

Defining GTKDOCIZE ensures, that autoreconf succeeds without gtkdocize.

Fixes:
http://autobuild.buildroot.net/results/d0259d1f8bed195e35338ead6c7c33fcc571497a/

Signed-off-by: Daniel Lang <d.lang@abatec.at>
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

package/autoconf/autoconf.mk

@@ -23,4 +23,4 @@ $(eval $(host-autotools-package))
 # variables used by other packages
 AUTOCONF = $(HOST_DIR)/bin/autoconf -I "$(ACLOCAL_DIR)" -I "$(ACLOCAL_HOST_DIR)"
 AUTOHEADER = $(HOST_DIR)/bin/autoheader -I "$(ACLOCAL_DIR)" -I "$(ACLOCAL_HOST_DIR)"
-AUTORECONF = $(HOST_CONFIGURE_OPTS) ACLOCAL="$(ACLOCAL)" AUTOCONF="$(AUTOCONF)" AUTOHEADER="$(AUTOHEADER)" AUTOMAKE="$(AUTOMAKE)" AUTOPOINT=/bin/true $(HOST_DIR)/bin/autoreconf -f -i
+AUTORECONF = $(HOST_CONFIGURE_OPTS) ACLOCAL="$(ACLOCAL)" AUTOCONF="$(AUTOCONF)" AUTOHEADER="$(AUTOHEADER)" AUTOMAKE="$(AUTOMAKE)" AUTOPOINT=/bin/true GTKDOCIZE=/bin/true $(HOST_DIR)/bin/autoreconf -f -i