Added new simplified C + D tests. Removed straggling full test skeleton files.

tests/app_5/CMakeLists.txt

@@ -0,0 +1,7 @@
+# This is a D app that links a C object.
+#
+# The linker preference of D is higher than C (or CXX), so after
+# the objects are created, the D toolchain will drive linking.
+#
+ADD_EXECUTABLE ( app_5 app_5.d cfunc.c )
+ADD_TEST( app_5 app_5 )

tests/app_5/app_5.d

@@ -0,0 +1,9 @@
+extern(C) int cfunc( int x );
+int main()
+{
+	int x = 1;
+	int y;
+	y = cfunc(x);
+	assert( y == x + 1 );
+	return 0;
+}

tests/app_5/cfunc.c

@@ -0,0 +1,4 @@
+int cfunc( int x )
+{
+	return x + 1;
+}