Added the ability for the "make" command to take a triple:

% cd lldb/test/lang/c/array_types
% make TRIPLE=x86_64-apple-ios
% make clean
% make TRIPLE=x86_64-apple-ios8.1
% make clean
% make TRIPLE=armv7-apple-ios
% make clean
% make TRIPLE=armv7-apple-ios8.1
% make clean

The TRIPLE variable will automatically set the following variables:
    SDKROOT if it isn't specified manually
    ARCH will be set to the architecture from the triple
    CFLAGS will include the extras needed for the triple which are set in TRIPLE_CFLAGS
    TRIPLE_VENDOR set to the triple vendor ("apple" in the above cases)
    TRIPLE_OS set to the triple OS ("ios" in the above cases)
    TRIPLE_VERSION set to the version that was specified, or automatically set to the SDK version if it is missing

This allows you to change directory into any test case on MacOSX and quickly build for desktop:

% make

iOS simulator:

% make TRIPLE=x86_64-apple-ios

or iOS device:

% make TRIPLE=armv7-apple-ios

llvm-svn: 238869