[sysprof] build: document more of meson_options.txt

[Christian Hergert <chergert src gnome org>]

commit a48887a25c7bcdb595c17411b0ec59ae053ab294
Author: Christian Hergert <chergert redhat com>
Date:   Tue May 7 14:50:48 2019 -0700

    build: document more of meson_options.txt

 meson_options.txt | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
---
diff --git a/meson_options.txt b/meson_options.txt
index 797b231..b04a0d4 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -1,11 +1,25 @@
+# Optionally disable the GTK application in case you're building the
+# sysprof-cli only for your platform. Might be useful in IoT or various
+# server scenarios.
 option('enable_gtk', type: 'boolean')
+
+# Optionally compile sysprofd, which is needed to get elevated privileges.
+# You only really want to ignore this if you are running from a container
+# and are talking to a host daemon. Also, if you're compiling for something
+# other than Linux to allow viewing syscap files.
 option('with_sysprofd', type: 'combo',
   choices: ['host', 'bundled', 'none'],
   value: 'bundled',
 )
+
+# The directory to place systemd service files, so that we can auto-launch
+# sysprofd as necessary (for the daemon privilege helper).
 option('systemdunitdir', type: 'string',
   description: 'Directory for systemd service files'
 )
+
+# An optional location to specify where to locate debug information. This
+# is useful for distributions to set based on their debuginfo setup.
 option('debugdir', type: 'string',
   description: 'Look for global separate debug info in this path'
 )