test: preparser: disable tests with external process where it can't be run

We could still test the part that use the internal preparser.

test/src/preparser/cmp_internal_external.c

@@ -254,6 +254,9 @@ static void test_preparser_cmp(vlc_object_t *obj, int i)
 
 int main( void )
 {
+#if !defined(HAVE_VLC_PROCESS_SPAWN)
+    return 77;
+#else
     test_init();
 
     static const char * argv[] = {
@@ -268,4 +271,5 @@ int main( void )
     }
 
     libvlc_release( vlc );
+#endif
 }

test/src/preparser/thumbnail.c

@@ -249,9 +249,11 @@ int main( void )
     test_thumbnails( vlc, false );
     test_cancel_thumbnail( vlc, false );
 
+#if !defined(HAVE_VLC_PROCESS_SPAWN)
     fprintf(stderr, "Run with external preparser...\n");
     test_thumbnails( vlc, true );
     test_cancel_thumbnail( vlc, true );
+#endif
 
 
     libvlc_release( vlc );

test/src/preparser/thumbnail_to_files.c

@@ -372,11 +372,13 @@ int main(int argc, const char *argv[])
     if (ret != 0) {
         goto end;
     }
+#if !defined(HAVE_VLC_PROCESS_SPAWN)
     fprintf(stderr, "Run with external preparser...\n");
     ret = run_test(vlc, true);
     if (ret != 0) {
         goto end;
     }
+#endif
 
 end:
     libvlc_release(vlc);