Rename libgvc to libgnome-volume-control to prevent
soname collision with graphviz.

diff -ur a/subprojects/gvc/meson.build b/subprojects/gvc/meson.build
--- a/subprojects/gvc/meson.build	2025-01-22 16:01:29.637007998 +0100
+++ b/subprojects/gvc/meson.build	2025-01-22 16:03:14.217729940 +0100
@@ -78,7 +78,7 @@
 endif
 
 if enable_static
-  libgvc_static = static_library('gvc',
+  libgvc_static = static_library('gnome-volume-control',
     sources: libgvc_gir_sources + libgvc_no_gir_sources + libgvc_enums,
     dependencies: libgvc_deps,
     c_args: c_args
@@ -90,7 +90,7 @@
     error('Installing shared library, but pkglibdir is unset!')
   endif
 
-  libgvc_shared = shared_library('gvc',
+  libgvc_shared = shared_library('gnome-volume-control',
     sources: libgvc_gir_sources + libgvc_no_gir_sources + libgvc_enums,
     dependencies: libgvc_deps,
     c_args: c_args,