Собственно, сабж. В гугле три невнятных ссылки, по одной из которых страница уже удалена. На ЛОРе вопрос тоже как-то не получил развития. А такая проблема таки есть, и иногда всплывает.
Напоролся на неё при сборке glib 2.60.0 этими вашими meson'ом и ninja'ей.
Found ninja-1.9.0 at /usr/bin/ninja
[1112/1152] Generating glib-gettextize-man with a custom command.
FAILED: docs/reference/glib/glib-gettextize.1
/usr/bin/xsltproc --nonet --stringparam man.output.quietly 1 --stringparam funcsynopsis.style ansi --stringparam man.th.extra1.suppress 1 --stringparam man.authors.section.enabled 0 --stringparam man.copyright.section.enabled 0 -o docs/reference/glib/glib-gettextize.1 http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl ../docs/reference/glib/glib-gettextize.xml
I/O error : Attempt to load network entity http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
warning: failed to load external entity "http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"
cannot parse http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
[1113/1152] Generating gtester-man with a custom command.
FAILED: docs/reference/glib/gtester.1
/usr/bin/xsltproc --nonet --stringparam man.output.quietly 1 --stringparam funcsynopsis.style ansi --stringparam man.th.extra1.suppress 1 --stringparam man.authors.section.enabled 0 --stringparam man.copyright.section.enabled 0 -o docs/reference/glib/gtester.1 http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl ../docs/reference/glib/gtester.xml
I/O error : Attempt to load network entity http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
warning: failed to load external entity "http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"
cannot parse http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
[1115/1152] Generating gtester-report-man with a custom command.
FAILED: docs/reference/glib/gtester-report.1
/usr/bin/xsltproc --nonet --stringparam man.output.quietly 1 --stringparam funcsynopsis.style ansi --stringparam man.th.extra1.suppress 1 --stringparam man.authors.section.enabled 0 --stringparam man.copyright.section.enabled 0 -o docs/reference/glib/gtester-report.1 http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl ../docs/reference/glib/gtester-report.xml
I/O error : Attempt to load network entity http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
warning: failed to load external entity "http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"
cannot parse http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl
[1129/1152] Compiling C object 'gio/tests/bcb7ac7@@gdbus-t...@exe/meson-generated_.._gdbus-test-codegen-generated.c.o'.
ninja: build stopped: subcommand failed.
