Suppress -Wunnecessary-virtual-specifier

With clang update, building code using llvm-project headers from older
version triggers the following build errors:

external/swiftshader/third_party/llvm-10.0/llvm/lib/Target/X86/X86InstrInfo.h:136:16:
 error: virtual method 'anchor' is inside a 'final' class and can never be overridden [-Werror,-Wunnecessary-virtual-specifier]
external/swiftshader/third_party/llvm-16.0/llvm/include/llvm/IR/ConstantFolder.h:31:16:
 error: virtual method 'anchor' is inside a 'final' class and can never be overridden [-Werror,-Wunnecessary-virtual-specifier]

So suppress -Wunnecessary-virtual-specifier when llvm-project headers
are used.

Bug: 452729455
Test: build with clang update
Change-Id: Ideadeaae7bebb945bc8f87a5aed419731afc0c14
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/76828
Presubmit-Ready: Geoff Lang <geofflang@google.com>
Commit-Queue: Geoff Lang <geofflang@google.com>
Reviewed-by: Geoff Lang <geofflang@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Geoff Lang <geofflang@google.com>

src/Android.bp

diff --git a/src/Android.bp b/src/Android.bp
index 51c8ca0..bd9e725 100644
--- a/src/Android.bp
+++ b/src/Android.bp
@@ -48,6 +48,8 @@
         "-DREACTOR_ANONYMOUS_MMAP_NAME=swiftshader_jit",
         "-Wno-unused-parameter",
         "-Wno-implicit-fallthrough",
+        // This warning can be re-enabled after updating to newer llvm version.
+        "-Wno-unnecessary-virtual-specifier",
     ],
 
     static_libs: [

third_party/llvm-10.0/Android.bp

diff --git a/third_party/llvm-10.0/Android.bp b/third_party/llvm-10.0/Android.bp
index f124687..f1a8646 100644
--- a/third_party/llvm-10.0/Android.bp
+++ b/third_party/llvm-10.0/Android.bp
@@ -1052,6 +1052,8 @@
         "-Wno-unreachable-code-loop-increment",
         "-Wno-unused-parameter",
         "-Wno-unused-variable",
+        // This warning can be re-enabled after updating to newer llvm version.
+        "-Wno-unnecessary-virtual-specifier",
     ],
 
     sanitize: {

third_party/llvm-16.0/Android.bp

diff --git a/third_party/llvm-16.0/Android.bp b/third_party/llvm-16.0/Android.bp
index c382558..06be43c 100644
--- a/third_party/llvm-16.0/Android.bp
+++ b/third_party/llvm-16.0/Android.bp
@@ -1502,6 +1502,8 @@
         "-Wno-unreachable-code-loop-increment",
         "-Wno-unused-parameter",
         "-Wno-unused-variable",
+        // This warning can be re-enabled after updating to newer llvm version.
+        "-Wno-unnecessary-virtual-specifier",
         "-DBLAKE3_NO_AVX512",
         "-DBLAKE3_NO_AVX2",
         "-DBLAKE3_NO_SSE41",