llvmpipe: Set "+64bit" for X86_64

Without this, on some "buggy" qemu cpu setup, LLVM could crash
if LLVM detects the wrong CPU type.

Fixes: f92cadccc6 ("llvmpipe: Always using util_get_cpu_caps to get cpu caps for llvm on x86")

Signed-off-by: Lepton Wu <lepton@chromium.org>
Reviewed-by: Yonggang Luo <luoyonggang@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/27539>
(cherry picked from commit 04d26ceb0a)

.pick_status.json

@@ -1154,7 +1154,7 @@
         "description": "llvmpipe: Set \"+64bit\" for X86_64",
         "nominated": true,
         "nomination_type": 1,
-        "resolution": 0,
+        "resolution": 1,
         "main_sha": null,
         "because_sha": "f92cadccc65128fdaa54e59ba40dcf75e90a25dd",
         "notes": null

src/gallium/auxiliary/gallivm/lp_bld_misc.cpp

@@ -416,6 +416,13 @@ lp_build_create_jit_compiler_for_module(LLVMExecutionEngineRef *OutJIT,
     * so we do not use llvm::sys::getHostCPUFeatures to detect cpu features
     * but using util_get_cpu_caps() instead.
     */
+#if DETECT_ARCH_X86_64
+   /*
+    * Without this, on some "buggy" qemu cpu setup, LLVM could crash
+    * if LLVM detects the wrong CPU type.
+    */
+   MAttrs.push_back("+64bit");
+#endif
    MAttrs.push_back(util_get_cpu_caps()->has_sse    ? "+sse"    : "-sse"   );
    MAttrs.push_back(util_get_cpu_caps()->has_sse2   ? "+sse2"   : "-sse2"  );
    MAttrs.push_back(util_get_cpu_caps()->has_sse3   ? "+sse3"   : "-sse3"  );