fix: pkg: Fix cross builds

Cross-compilation did not work even when the ``-Ddoc=disabled`` build
option was passed to Meson due to the build targets used for generating
documentation depending on a non-native executable. This has been fixed.

See #5379

Merge branch '5379-fix-cross-builds' into 'main'

See merge request isc-projects/bind9!10702

doc/meson.build

@@ -11,7 +11,6 @@
 
 # Manpages can be build without sphinx
 subdir('man')
-subdir('misc')
 
 if not sphinx_build.found()
     subdir_done()
@@ -19,3 +18,4 @@ endif
 
 subdir('arm')
 subdir('dnssec-guide')
+subdir('misc')

meson.build

@@ -1630,8 +1630,6 @@ alias_target('system-test-dependencies', system_test_targets)
 
 ### Documentation
 
-alias_target('doc-misc', doc_misc_targets)
-
 get_release_date = '''
 import os
 import datetime
@@ -1663,6 +1661,8 @@ if doc_opt.allowed()
     install_man(man_pages)
 
     if sphinx_build.found()
+        alias_target('doc-misc', doc_misc_targets)
+
         meson.add_dist_script(
             'util' / 'meson-dist-package.sh',
             'manual',