[scan-build] Patch to scan-build tool to support "--target=<value>" flag

The scan-build script provided by clang can be used to detect defects in
code in the compile time. However, we discovered that the
"--target=<value>" flag in clang is not properly handled by this script,
which results in failures when analyzing projects that have used this
flag in their makefile.

This single line of change allows scan-build script to properly handle
the "--target=<value>" flag.

Patch by Haowei Wu

Differential Revision: https://reviews.llvm.org/D33263

llvm-svn: 304025