gallivm: Fix x86 build with llvm-3.0svn.

LLVM revision 133739 renamed StackAlignment to StackAlignmentOverride.

src/gallium/auxiliary/gallivm/lp_bld_misc.cpp

@@ -83,8 +83,12 @@ lp_set_target_options(void)
     * to only assume a 4 bytes alignment for backwards compatibility.
     */
 #if defined(PIPE_ARCH_X86)
+#if HAVE_LLVM >= 0x0300
+   llvm::StackAlignmentOverride = 4;
+#else
    llvm::StackAlignment = 4;
 #endif
+#endif
 
 #if defined(DEBUG) || defined(PROFILE)
    llvm::NoFramePointerElim = true;