meson.build: adds summary() to optional programs

doc/meson.build

@@ -4,7 +4,9 @@ doxyfile_conf.set('PACKAGE_VERSION', meson.project_version())
 doxyfile_conf.set('top_srcdir', meson.source_root())
 doxyfile_conf.set('top_builddir', meson.build_root())
 
-if find_program('dot', required: false).found()
+dot_found = find_program('dot', required: false).found()
+summary({'dot (used with doxygen)': dot_found}, bool_yn: true, section: 'Optional programs')
+if dot_found
   doxyfile_conf.set('HAVE_DOT', 'YES')
 else
   doxyfile_conf.set('HAVE_DOT', 'NO')
@@ -37,6 +39,7 @@ endif
 # Because this uses globbing, this target won't rebuild if the headers
 # change but meh.
 sed = find_program('sed', required: false)
+summary({'sed (for SPA docs)': sed.found()}, bool_yn: true, section: 'Optional programs')
 if sed.found()
   spa_srcdir = meson.source_root() / 'spa' / 'include' / 'spa'
   spa_dstdir = meson.current_build_dir() / 'spa'

spa/tests/meson.build

@@ -2,6 +2,7 @@
 # ones which have circular dependencies and take some effort to fix.
 # Do it for C++ if possible (picks up C++-specific errors), otherwise for C.
 find = find_program('find', required: false)
+summary({'find (for header testing)': find.found()}, bool_yn: true, section: 'Optional programs')
 if find.found()
   spa_headers = run_command(find,
                             meson.source_root() / 'spa' / 'include',

test/meson.build

@@ -85,6 +85,7 @@ test('test spa',
 )
 
 valgrind = find_program('valgrind', required: false)
+summary({'valgrind (test setup)': valgrind.found()}, bool_yn: true, section: 'Optional programs')
 if valgrind.found()
   valgrind_env = environment()
   add_test_setup('valgrind',