Add a workaround to silence a bogus g++-4.4 -pedantic warning.
Add a workaround to silence a bogus g++-4.4 -pedantic warning.

driver.cpp:211: warning: ISO C++ forbids zero-size array 'argv'


git-svn-id: ffe668792ed300d6c2daa1f6eba2e0aa28d7ec6c@89455 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang,llvm-mirror/clang,apple/swift-clang,llvm-mirror/clang,apple/swift-clang,apple/swift-clang,llvm-mirror/clang