[libpng16] Updated CMakeLists.txt, added supporting scripts/gen*.cmake.in

and test.cmake.in

scripts/test.cmake.in

@@ -0,0 +1,22 @@
+set(TEST_OPTIONS "@TEST_OPTIONS@")
+set(TEST_FILES "@TEST_FILES@")
+
+foreach(file ${TEST_FILES})
+  file(TO_NATIVE_PATH "${file}" native_file)
+  list(APPEND NATIVE_TEST_FILES "${native_file}")
+endforeach()
+
+# Add the directory containing libpng to the PATH (Windows only)
+if(WIN32)
+  get_filename_component(LIBPNG_DIR "${LIBPNG}" PATH)
+  file(TO_NATIVE_PATH "${LIBPNG_DIR}" LIBPNG_DIR)
+  set(ENV{PATH} "${LIBPNG_DIR};$ENV{PATH}")
+endif()
+
+execute_process(COMMAND "${CMAKE_COMMAND}" -E echo "Running ${TEST_COMMAND}" ${TEST_OPTIONS} ${NATIVE_TEST_FILES})
+
+execute_process(COMMAND "${TEST_COMMAND}" ${TEST_OPTIONS} ${NATIVE_TEST_FILES}
+                RESULT_VARIABLE TEST_STATUS)
+if(TEST_STATUS)
+  message(FATAL_ERROR "Returned failed status ${TEST_STATUS}!")
+endif()