Ensure `--vips-config` only prints build configuration (#3062)

Also, remove a remnant of Autotools.

libvips/include/vips/meson.build

@@ -88,7 +88,8 @@ foreach _, section : build_summary
     foreach key, arr : section
         if key.contains('gtk-doc') or \
            key.contains('doxygen') or \
-           key.contains('introspection')
+           key.contains('introspection') or \
+           key.contains('examples')
            continue
         endif
 

libvips/iofuncs/init.c

@@ -1251,7 +1251,7 @@ vips_version_string( void )
  * Get the major, minor or micro library version, with @flag values 0, 1 and
  * 2.
  *
- * Get the ABI current, revision and age (as used by libtool) with @flag 
+ * Get the ABI current, revision and age (as used by Meson) with @flag 
  * values 3, 4, 5. 
  *
  * Returns: library version number

libvips/resample/dummy2.cc

@@ -1,4 +0,0 @@
-/* mac os x libtool needs to link libraries containing c++ (eg. cimg) with 
- * g++ ... force this with a dummy c++ file at the top level
- */
-const int im__dummy_value = 42;