[PATCH] BaseTools/tools_def: Disable overzealous unused variable warning on Clang

["Ard Biesheuvel" <ardb@kernel.org>]

The warnings Clang emits when enabling -Wunneeded-internal-declaration
(which is part of -Wall) are generating false positives for variables
whose size gets taken but are not referenced beyond that.

This may happen legitimately in debug code, so let's disable this
warning for Clang, rather than tiptoe around it in the code base.

This fixes the RELEASE build for OVMF, which triggers this issue in the
newly added VirtioSerialDxe driver.

Cc: Rebecca Cran <rebecca@bsdio.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
Reproducer: https://godbolt.org/z/zx6qqjKrK

 BaseTools/Conf/tools_def.template | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/BaseTools/Conf/tools_def.template b/BaseTools/Conf/tools_def.template
index b3c822f0bc20046d..65dde57631fb6c95 100755
--- a/BaseTools/Conf/tools_def.template
+++ b/BaseTools/Conf/tools_def.template
@@ -1858,7 +1858,7 @@ DEFINE CLANGDWARF_X64_DLINK2_FLAGS        = -Wl,--defsym=PECOFF_HEADER_SIZE=0x22
 DEFINE CLANGDWARF_IA32_TARGET             = -target i686-pc-linux-gnu
 DEFINE CLANGDWARF_X64_TARGET              = -target x86_64-pc-linux-gnu
 
-DEFINE CLANGDWARF_WARNING_OVERRIDES    = -Wno-parentheses-equality -Wno-tautological-compare -Wno-tautological-constant-out-of-range-compare -Wno-empty-body -Wno-unused-const-variable -Wno-varargs -Wno-unknown-warning-option -Wno-unused-but-set-variable -Wno-unused-const-variable -Wno-unaligned-access
+DEFINE CLANGDWARF_WARNING_OVERRIDES    = -Wno-parentheses-equality -Wno-tautological-compare -Wno-tautological-constant-out-of-range-compare -Wno-empty-body -Wno-unused-const-variable -Wno-varargs -Wno-unknown-warning-option -Wno-unused-but-set-variable -Wno-unused-const-variable -Wno-unaligned-access -Wno-unneeded-internal-declaration
 DEFINE CLANGDWARF_ALL_CC_FLAGS         = DEF(GCC48_ALL_CC_FLAGS) DEF(CLANGDWARF_WARNING_OVERRIDES) -fno-stack-protector -mms-bitfields -Wno-address -Wno-shift-negative-value -Wno-unknown-pragmas -Wno-incompatible-library-redeclaration -fno-asynchronous-unwind-tables -mno-sse -mno-mmx -msoft-float -mno-implicit-float  -ftrap-function=undefined_behavior_has_been_optimized_away_by_clang -funsigned-char -fno-ms-extensions -Wno-null-dereference
 
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-- 
2.39.2