Since commit 571dc748 (Recognize Clang C and C++ compilers, 2010-05-17)
we recognize Clang C and C++ support. Add Compiler/Clang-ASM.cmake to
enable use of Clang for ASM too. Also teach Assembler test to try Clang
as an assembler.
Suggested-by: Tobias Pape <tobiaspape@gmail.com>
Brad King