meson: Stop looking for udevadm at build time

We only use it at runtime, not during the build process.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Pavel Hrdina <phrdina@redhat.com>

meson.build

@@ -820,7 +820,6 @@ optional_programs = [
   'rmmod',
   'scrub',
   'tc',
-  'udevadm',
 ]
 
 foreach name : optional_programs

src/util/virutil.c

@@ -62,6 +62,8 @@ G_STATIC_ASSERT(sizeof(gid_t) <= sizeof(unsigned int) &&
 
 VIR_LOG_INIT("util.util");
 
+#define UDEVADM "udevadm"
+
 #ifndef WIN32
 
 int virSetInherit(int fd, bool inherit)