gn build: Use -fvisibility-global-new-delete=force-hidden to build libcxx/libcxxabi/libunwind.

-fvisibility-global-new-delete-hidden is deprecated and clang was warning
about it on every build command. These libraries are always built using
a stage2 compiler, so we can use the new build flag unconditionally.

Reviewers: aeubanks

Reviewed By: aeubanks

Pull Request: #88459

Author: pcc

llvm/utils/gn/secondary/libcxx/src/BUILD.gn

@@ -291,7 +291,7 @@ if (libcxx_enable_static) {
     if (libcxx_hermetic_static_library) {
       cflags = [ "-fvisibility=hidden" ]
       if (libcxx_enable_new_delete_definitions) {
-        cflags_cc = [ "-fvisibility-global-new-delete-hidden" ]
+        cflags_cc = [ "-fvisibility-global-new-delete=force-hidden" ]
       }
       defines = [ "_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS" ]
     }

llvm/utils/gn/secondary/libcxxabi/src/BUILD.gn

@@ -116,7 +116,7 @@ if (libcxxabi_enable_static) {
     if (libcxxabi_hermetic_static_library) {
       cflags = [ "-fvisibility=hidden" ]
       if (libcxxabi_enable_new_delete_definitions) {
-        cflags_cc = [ "-fvisibility-global-new-delete-hidden" ]
+        cflags_cc = [ "-fvisibility-global-new-delete=force-hidden" ]
       }
       defines = [
         "_LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS",

llvm/utils/gn/secondary/libunwind/src/BUILD.gn

@@ -119,7 +119,7 @@ if (libunwind_enable_static) {
       public = unwind_headers
       if (!invoker.export) {
         cflags = [ "-fvisibility=hidden" ]
-        cflags_cc = [ "-fvisibility-global-new-delete-hidden" ]
+        cflags_cc = [ "-fvisibility-global-new-delete=force-hidden" ]
         defines = [ "_LIBUNWIND_HIDE_SYMBOLS" ]
       }
       deps = [ "//compiler-rt/lib/builtins" ]