[CMake] bug or feature with SET_SOURCE_FILES_PROPERTIES?

[Brad King]

Prakash Punnoor wrote:
>       SET(TEST_SRC test/test${TEST}.c)
>       SET_SOURCE_FILES_PROPERTIES(${TEST_SRC} PROPERTIES COMPILE_FLAGS
> "-Wno-unused")
[snip]
>     SET_SOURCE_FILES_PROPERTIES(test/testcpp.cc PROPERTIES COMPILE_FLAGS
> "-Wno-unused")

One version has a .c and the other has a .cc suffix on the file.

-Brad