Bug#894069: libgtk-3-dv: AM_PATH_GTK_3_0 misuses AC_PATH_PROG

[Simon McVittie]

Control: forwarded -1 https://gitlab.gnome.org/GNOME/gtk/issues/133

On Mon, 26 Mar 2018 at 06:28:44 +0200, Helmut Grohne wrote:
> If AM_PATH_GTK_3_0 was using PKG_PROG_PKG_CONFIG or even
> PKG_CHECK_MODULES, this problem would have gone away entirely. Is there
> a reason for not using these macros?

AM_PATH_GTK_3_0 is itself deprecated in favour of PKG_CHECK_MODULES
(officially since 2014, but its removal was already proposed in 2011).
I assume that the more-correct pkg-config macros were either unavailable
or not widely known at the time this macro was written.

Deprecation:
https://bugzilla.gnome.org/show_bug.cgi?id=641638

as a result of a previous bug in this macro that caused FTBFS when
pkg-config's behaviour changed:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=756476

I thought GLib might have the same bug, but it turns out to have been
fixed in 2007:
https://bugzilla.gnome.org/show_bug.cgi?id=392636

GTK 2 also has this bug (but worse, because it hard-codes pkg-config in
one place where GTK 3 correctly uses $PKG_CONFIG).

    smcv