GTKDOC_DEPS in recent gtk-doc.m4

[Simon Josefsson <simon josefsson org>]

Hi!  I'm using gtk-doc in for example GNU Libtasn1 and recently upgraded
to the latest gtk-doc.m4 from your git repo, which contains this new
piece of code:

    dnl don't check for glib if we build glib
    if test "x$PACKAGE_NAME" != "xglib"; then
      dnl don't fail if someone does not have glib
      PKG_CHECK_MODULES(GTKDOC_DEPS, glib-2.0 >= 2.10.0 gobject-2.0  >= 2.10.0,,)
    fi

This causes ./configure failures for me, see output below.  I don't
understand the intention of the code above.  For what does gtk-doc need
glib-2.0 and gobject-2.0?  GTK-DOC has worked fine for me and produced
good output even without those dependencies.

If possible, I don't want GNU Libtasn1 users to have to install glib and
gobject to be able to build documentation.

/Simon

checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for gtkdoc-check... /usr/bin/gtkdoc-check
checking for gtkdoc-rebase... /usr/bin/gtkdoc-rebase
checking for gtkdoc-mkpdf... /usr/bin/gtkdoc-mkpdf
checking for GTKDOC_DEPS... configure: error: Package requirements (glib-2.0 >= 2.10.0 gobject-2.0  >= 2.10.0) were not met:

No package 'glib-2.0' found
No package 'gobject-2.0' found

Consider adjusting the PKG_CONFIG_PATH environment variable if you
installed software in a non-standard prefix.

Alternatively, you may set the environment variables GTKDOC_DEPS_CFLAGS
and GTKDOC_DEPS_LIBS to avoid the need to call pkg-config.
See the pkg-config man page for more details.