Improve GObject-Introspection packaging (Closes: #1116569)

• d/control: Explicitly build-depend on the GIR XML that is needed

  At the moment these are pulled in by libgirepository1.0-dev, but we want to phase out that package before the forky release.

  This silences warnings from dh_girepository, and is a prerequisite for potentially enabling cross-compiling in a future version.

• d/control: Replace libgirepository1.0-dev B-D with gobject-introspection

  This is compatible with Debian >= 13 and Ubuntu >= 24.04, but will need to be reverted in backports to Debian 12 or Ubuntu 22.04.

  Closes: #1116569

• d/control: Remove unnecessary B-D on gir1.2-freedesktop

  I'm not sure why this was here: it was present in the initial packaging copied from gstreamer0.10 back in 2011. GStreamer doesn't seem to need any of the typelibs in that package.

---

I compiled a reference copy of gstreamer1.0 in sbuild without this MR, then recompiled with this MR, and got identical binaries produced (but noticeably fewer build-dependencies, see diffoscope output below). Not otherwise tested.

diffoscope

├── gstreamer1.0_1.26.6-1_amd64.buildinfo
│ ├── Build-Date
│ │ @@ -1 +1 @@
│ │ -Sun, 28 Sep 2025 15:24:22 +0000
│ │ +Sun, 28 Sep 2025 15:47:42 +0000
│ ├── Installed-Build-Depends
│ │ @@ -28,32 +28,25 @@
│ │   diffutils (= 1:3.10-4),
│ │   dpkg (= 1.22.21),
│ │   dpkg-dev (= 1.22.21),
│ │   dwz (= 0.16-2),
│ │   file (= 1:5.46-5),
│ │   findutils (= 4.10.0-3),
│ │   flex (= 2.6.4-8.2+b4),
│ │ - fontconfig-config (= 2.15.0-2.4),
│ │ - fonts-dejavu-core (= 2.37-8),
│ │ - fonts-dejavu-mono (= 2.37-8),
│ │   g++ (= 4:15.2.0-4),
│ │   g++-15 (= 15.2.0-4),
│ │   g++-15-x86-64-linux-gnu (= 15.2.0-4),
│ │   g++-x86-64-linux-gnu (= 4:15.2.0-4),
│ │   gcc (= 4:15.2.0-4),
│ │   gcc-15 (= 15.2.0-4),
│ │   gcc-15-base (= 15.2.0-4),
│ │   gcc-15-x86-64-linux-gnu (= 15.2.0-4),
│ │   gcc-x86-64-linux-gnu (= 4:15.2.0-4),
│ │   gettext (= 0.23.1-2+b1),
│ │   gettext-base (= 0.23.1-2+b1),
│ │ - gir1.2-freedesktop (= 1.86.0-5),
│ │ - gir1.2-freedesktop-dev (= 1.86.0-5),
│ │ - gir1.2-girepository-2.0 (= 1.86.0-5),
│ │ - gir1.2-girepository-2.0-dev (= 1.86.0-5),
│ │   gir1.2-glib-2.0 (= 2.84.4-3),
│ │   gir1.2-glib-2.0-dev (= 2.84.4-3),
│ │   girepository-tools (= 2.84.4-3),
│ │   gobject-introspection (= 1.86.0-5),
│ │   gobject-introspection-bin (= 1.86.0-5),
│ │   grep (= 3.12-1),
│ │   groff-base (= 1.23.0-9),
│ │ @@ -67,23 +60,20 @@
│ │   libatomic1 (= 15.2.0-4),
│ │   libattr1 (= 1:2.5.2-3),
│ │   libaudit-common (= 1:4.1.2-1),
│ │   libaudit1 (= 1:4.1.2-1),
│ │   libbinutils (= 2.45-7),
│ │   libblkid-dev (= 2.41.2-2),
│ │   libblkid1 (= 2.41.2-2),
│ │ - libbrotli1 (= 1.1.0-2+b7),
│ │   libbsd0 (= 0.12.2-2),
│ │   libbz2-1.0 (= 1.0.8-6),
│ │   libc-bin (= 2.41-12),
│ │   libc-dev-bin (= 2.41-12),
│ │   libc6 (= 2.41-12),
│ │   libc6-dev (= 2.41-12),
│ │ - libcairo-gobject2 (= 1.18.4-1+b1),
│ │ - libcairo2 (= 1.18.4-1+b1),
│ │   libcap-dev (= 1:2.75-10+b1),
│ │   libcap-ng0 (= 0.8.5-4+b1),
│ │   libcap2 (= 1:2.75-10+b1),
│ │   libcap2-bin (= 1:2.75-10+b1),
│ │   libcc1-0 (= 15.2.0-4),
│ │   libcrypt-dev (= 1:4.4.38-1),
│ │   libcrypt1 (= 1:4.4.38-1),
│ │ @@ -98,26 +88,22 @@
│ │   libedit2 (= 3.1-20250104-1),
│ │   libelf-dev (= 0.193-3),
│ │   libelf1t64 (= 0.193-3),
│ │   libexpat1 (= 2.7.3-1),
│ │   libffi-dev (= 3.5.2-2),
│ │   libffi8 (= 3.5.2-2),
│ │   libfile-stripnondeterminism-perl (= 1.15.0-1),
│ │ - libfontconfig1 (= 2.15.0-2.4),
│ │ - libfreetype6 (= 2.13.3+dfsg-1),
│ │   libgcc-15-dev (= 15.2.0-4),
│ │   libgcc-s1 (= 15.2.0-4),
│ │   libgdbm-compat4t64 (= 1.26-1),
│ │   libgdbm6t64 (= 1.26-1),
│ │   libgio-2.0-dev (= 2.84.4-3),
│ │   libgio-2.0-dev-bin (= 2.84.4-3),
│ │   libgirepository-1.0-1 (= 1.86.0-5),
│ │ - libgirepository-1.0-dev (= 1.86.0-5),
│ │   libgirepository-2.0-0 (= 2.84.4-3),
│ │ - libgirepository1.0-dev (= 1.86.0-5),
│ │   libglib2.0-0t64 (= 2.84.4-3),
│ │   libglib2.0-bin (= 2.84.4-3),
│ │   libglib2.0-data (= 2.84.4-3),
│ │   libglib2.0-dev (= 2.84.4-3),
│ │   libglib2.0-dev-bin (= 2.84.4-3),
│ │   libgmp-dev (= 2:6.3.0+dfsg-5),
│ │   libgmp10 (= 2:6.3.0+dfsg-5),
│ │ @@ -150,17 +136,15 @@
│ │   libpcre2-16-0 (= 10.46-1),
│ │   libpcre2-32-0 (= 10.46-1),
│ │   libpcre2-8-0 (= 10.46-1),
│ │   libpcre2-dev (= 10.46-1),
│ │   libpcre2-posix3 (= 10.46-1),
│ │   libperl5.40 (= 5.40.1-6),
│ │   libpipeline1 (= 1.5.8-1),
│ │ - libpixman-1-0 (= 0.44.0-3),
│ │   libpkgconf3 (= 1.8.1-4),
│ │ - libpng16-16t64 (= 1.6.50-1),
│ │   libpython3-stdlib (= 3.13.7-1),
│ │   libpython3.13-minimal (= 3.13.7-1),
│ │   libpython3.13-stdlib (= 3.13.7-1),
│ │   libquadmath0 (= 15.2.0-4),
│ │   libreadline8t64 (= 8.3-3),
│ │   libseccomp2 (= 2.6.0-2),
│ │   libselinux1 (= 3.8.1-1),
│ │ @@ -183,24 +167,15 @@
│ │   libubsan1 (= 15.2.0-4),
│ │   libuchardet0 (= 0.0.8-2),
│ │   libudev1 (= 258-1),
│ │   libunistring5 (= 1.3-2),
│ │   libunwind-dev (= 1.8.1-0.1),
│ │   libunwind8 (= 1.8.1-0.1),
│ │   libuuid1 (= 2.41.2-2),
│ │ - libx11-6 (= 2:1.8.12-1),
│ │ - libx11-data (= 2:1.8.12-1),
│ │ - libxau6 (= 1:1.0.11-1),
│ │ - libxcb-render0 (= 1.17.0-2+b1),
│ │ - libxcb-shm0 (= 1.17.0-2+b1),
│ │ - libxcb1 (= 1.17.0-2+b1),
│ │ - libxdmcp6 (= 1:1.1.5-1),
│ │ - libxext6 (= 2:1.3.4-1+b3),
│ │   libxml2-16 (= 2.14.5+dfsg-0.2),
│ │ - libxrender1 (= 1:0.9.12-1),
│ │   libz3-4 (= 4.13.3-1),
│ │   libzstd-dev (= 1.5.7+dfsg-1.1),
│ │   libzstd1 (= 1.5.7+dfsg-1.1),
│ │   linux-libc-dev (= 6.16.9-1),
│ │   m4 (= 1.4.20-1),
│ │   make (= 4.4.1-2),
│ │   man-db (= 2.13.1-1),