[Buildroot] [git commit branch/2022.08.x] package/usbguard: fix build without asciidoc

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=2acbcd1cc69f8ea08235214bb74080b5bd07a8a0
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2022.08.x

Set ac_cv_prog_A2X to disable build of documentation and avoid the
following build failure without a working a2x raised since at least bump
to version 1.1.1 in commit ad21d84a589458fd4542993912891daa503d72dd:

a2x -v -f manpage doc/man/usbguard.1.adoc -D ./$(dirname doc/man/usbguard.1.roff)
a2x -v -f manpage doc/man/usbguard-dbus.8.adoc -D ./$(dirname doc/man/usbguard-dbus.8.roff)
/nvmedata/autobuild/instance-5/output-1/host/bin/python3: Error while finding module specification for 'asciidoc.a2x' (ModuleNotFoundError: No module named 'asciidoc')

Fixes:
 - http://autobuild.buildroot.org/results/e41950f3cd4bd83d9b067af498757cb9d2f207ef

Signed-off-by: Fabrice Fontaine <fontaine.fabrice at gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit cff78c34fbf80880c39725049ff42c3dd632fd7a)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/usbguard/usbguard.mk | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/usbguard/usbguard.mk b/package/usbguard/usbguard.mk
index 26dc40d15b..cf8f883485 100644
--- a/package/usbguard/usbguard.mk
+++ b/package/usbguard/usbguard.mk
@@ -10,6 +10,7 @@ USBGUARD_LICENSE = GPL-2.0+
 USBGUARD_LICENSE_FILES = LICENSE
 USBGUARD_CPE_ID_VENDOR = usbguard_project
 USBGUARD_SELINUX_MODULES = usbguard
+USBGUARD_CONF_ENV = ac_cv_prog_A2X=""
 USBGUARD_CONF_OPTS = \
 	--with-bundled-catch \
 	--with-bundled-pegtl \