wasm: skip examples by default

This removes the need for specifying "-nomake examples"
on the configure line.

We are using static builds; building all of the examples
is too space and time consuming (especially time).

Change-Id: Iff23239ca7304b1d1cf734c8bf69ad3f8ef31844
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

config_help.txt

@@ -213,7 +213,8 @@ Component selection:
                          [libs and examples, also tools if not cross-building,
                          also tests if -developer-build]
   -nomake <part> ....... Exclude <part> from the list of parts to be built.
-  -compile-examples .... When unset, install only the sources of examples [yes]
+  -compile-examples .... When unset, install only the sources of examples
+                         [no on WebAssembly, otherwise yes]
   -gui ................. Build the Qt GUI module and dependencies [yes]
   -widgets ............. Build the Qt Widgets module and dependencies [yes]
   -no-dbus ............. Do not build the Qt D-Bus module

configure.json

@@ -1203,6 +1203,7 @@
         },
         "compile_examples": {
             "label": "Compile examples",
+            "autoDetect": "!config.wasm",
             "output": [ "privateConfig" ]
         },
         "incredibuild_xge": {