tools: add sysprof-agent

This is a program that can be communicated with over private D-Bus using
pipes to control a process. It is useful in an automated fashion from
tooling such as Builder.

This allows, when installed into SDKs like GNOMEs, to profile from inside
the container rather than from the outside. Such is useful when you need
to ensure you have access to LD_PRELOAD/etc within the context.

src/tools/meson.build

@@ -12,6 +12,14 @@ if get_option('libsysprof')
      install_dir: get_option('bindir'),
          install: true,
   )
+
+  sysprof_agent = executable('sysprof-agent',
+    ['sysprof-agent.c', ipc_agent_src],
+    dependencies: [libsysprof_dep],
+          c_args: tools_cflags,
+     install_dir: get_option('bindir'),
+         install: true,
+  )
 endif
 
 sysprof_cat = executable('sysprof-cat', 'sysprof-cat.c',