+ added support for constructing target triplets
* pass "-target triplet" when using an LLVM assembler
o removed no longer needed $DARWINVERSION and $ARCH parameters
* consistently use as_clang_gas when clang is used to assembler GAS-style
assembly, and rename as_llcm_clang to as_clang_llvm (for consistency)
* support pipe assembling when using clang on *nix in all cases
git-svn-id: trunk@45807 -