Added a 16-bit Hello World app.

tests/hello16.c

@@ -0,0 +1,14 @@
+// wcc test16.c -bt=os2 -fo=.obj -zq -od -ms -i="C:\WATCOM\h\os21x"
+// wlink name test16 sys os2 op q file test16.obj
+
+#define INCL_DOS
+#include <os2.h>
+
+int main(void)
+{
+    DosPutMessage(1, 32, "Hello from a 16-bit OS/2 .exe!\r\n");
+    return 0;
+}
+
+// end of hello16.c ...
+