libsysprof-gtk: start on GTK widgetry library

This is ultimately to replace libsysprof-ui, and will focus on the display
of capture files. Recording will be left to the sysprof application in
terms of UI, and other applications like IDEs will use the
libsysprof-profile API directly along with libsysprof-gtk for visualizing.

src/libsysprof-gtk/meson.build

@@ -0,0 +1,74 @@
+libsysprof_gtk_public_sources = [
+  'sysprof-callgraph-view.c',
+  'sysprof-weighted-callgraph-view.c',
+]
+
+libsysprof_gtk_private_sources = [
+]
+
+libsysprof_gtk_public_headers = [
+  'sysprof-gtk.h',
+
+  'sysprof-callgraph-view.h',
+  'sysprof-weighted-callgraph-view.h',
+]
+
+libsysprof_gtk_deps = [
+  dependency('gtk4', version: gtk_req_version),
+
+  libsysprof_analyze_dep,
+]
+
+libsysprof_gtk_resources = gnome.compile_resources(
+  'libsysprof-gtk-resources',
+  'libsysprof-gtk.gresource.xml',
+  c_name: 'libsysprof_gtk',
+)
+
+libsysprof_gtk_static = static_library(
+  'sysprof-gtk-@0@'.format(soname_major_version),
+  (libsysprof_gtk_public_sources +
+   libsysprof_gtk_private_sources +
+   libsysprof_gtk_resources +
+   mapped_ring_buffer_sources),
+
+    include_directories: [include_directories('.'),
+                          ipc_include_dirs,
+                          libsysprof_capture_include_dirs],
+           dependencies: libsysprof_gtk_deps,
+  gnu_symbol_visibility: 'hidden',
+)
+
+libsysprof_gtk_static_dep = declare_dependency(
+            link_with: libsysprof_gtk_static,
+         dependencies: libsysprof_gtk_deps,
+  include_directories: [include_directories('.'),
+                        libsysprof_capture_include_dirs],
+)
+
+libsysprof_gtk = library('sysprof-gtk-@0@'.format(soname_major_version),
+           dependencies: [libsysprof_gtk_static_dep],
+  gnu_symbol_visibility: 'hidden',
+                version: '@0@.0.0'.format(soname_major_version),
+        darwin_versions: '@0@.0'.format(soname_major_version),
+                install: true,
+)
+
+libsysprof_gtk_dep = declare_dependency(
+            link_with: libsysprof_gtk,
+         dependencies: libsysprof_gtk_deps,
+  include_directories: [include_directories('.'), libsysprof_capture_include_dirs],
+)
+meson.override_dependency('sysprof-gtk-@0@'.format(soname_major_version), libsysprof_gtk_dep)
+
+pkgconfig.generate(libsysprof_gtk,
+            subdirs: [sysprof_header_subdir],
+        description: 'Provides GTK widgets for sysprof visualizion',
+        install_dir: join_paths(get_option('libdir'), 'pkgconfig'),
+           requires: ['gtk4'],
+          variables: ['datadir=' + datadir_for_pc_file],
+)
+
+install_headers(libsysprof_gtk_public_headers, subdir: sysprof_header_subdir)
+
+subdir('tests')