Watcom: Avoid prompt from wmake about dll with no exports...

...by simply building a STATIC lib for the test, instead of a
SHARED one. Fixes test timeout on the Watcom dashboards.

Tests/EmptyDepends/CMakeLists.txt

@@ -12,4 +12,4 @@ add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/qrc_my.cxx
 add_custom_command(OUTPUT ${CMAKE_BINARY_DIR}/my.qrc
   COMMAND ${CMAKE_COMMAND} -E touch ${CMAKE_BINARY_DIR}/my.qrc)
 
-add_library(qrc SHARED ${CMAKE_BINARY_DIR}/qrc_my.cxx)
+add_library(qrc STATIC ${CMAKE_BINARY_DIR}/qrc_my.cxx)