meson: print configuration summary()

Fixes #249
diff --git a/doc/meson.build b/doc/meson.build
index 8b74c19..b46d350 100644
--- a/doc/meson.build
+++ b/doc/meson.build
@@ -1,3 +1,5 @@
+doc_targets = []
+
 docbook2man = find_program('docbook2man', required: get_option('doc-man'))
 docbook2txt = find_program('docbook2txt', required: get_option('doc-txt'))
 docbook2pdf = find_program('docbook2pdf', required: get_option('doc-pdf'))
@@ -83,6 +85,8 @@
 endforeach
 
 if docbook2man.found()
+  doc_targets += ['man']
+
   custom_target('devel-man',
     input: [fontconfig_devel_sgml, funcs_sgml],
     output: man_pages,
@@ -113,6 +117,8 @@
 endif
 
 if docbook2pdf.found()
+  doc_targets += ['PDF']
+
   custom_target('devel-pdf',
     input: [fontconfig_devel_sgml, funcs_sgml],
     output: 'fontconfig-devel.pdf',
@@ -131,6 +137,8 @@
 endif
 
 if docbook2txt.found()
+  doc_targets += ['Text']
+
   custom_target('devel-txt',
     input: [fontconfig_devel_sgml, funcs_sgml],
     output: 'fontconfig-devel.txt',
@@ -149,6 +157,8 @@
 endif
 
 if docbook2html.found()
+  doc_targets += ['HTML']
+
   custom_target('devel-html',
     input: [fontconfig_devel_sgml, funcs_sgml],
     output: 'fontconfig-devel.html',
diff --git a/meson.build b/meson.build
index 51aa821..12509aa 100644
--- a/meson.build
+++ b/meson.build
@@ -360,3 +360,15 @@
 install_headers(fc_headers, subdir: meson.project_name())
 
 meson.add_install_script('install-cache.py', fccache.full_path())
+
+# Summary
+if meson.version() >= '0.53'
+  doc_targets = get_variable('doc_targets', [])
+
+  summary({
+         'Documentation': (doc_targets.length() > 0 ? doc_targets : false),
+         'NLS': not get_option('nls').disabled(),
+         'Tests': not get_option('tests').disabled(),
+         'Tools': not get_option('tools').disabled(),
+         }, section: 'General', bool_yn: true, list_sep: ', ')
+endif