switch clang to -fno-common by default

Common variables will be flagged as errors by default.  This can
be overridden with -fcommon.

Cherry-pick this change that will be part of LLVM11.  We bring it
forward so we can finish fixing the fallout in the ports tree.

ok deraadt@ sthen@ mglocker@

1 files changed, 1 insertions, 1 deletions

diff --git a/gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp b/gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp
index e33e80f5b37..f47906798a0 100644
--- a/gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/gnu/llvm/clang/lib/Frontend/CompilerInvocation.cpp
@@ -808,7 +808,7 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
   Opts.DwarfDebugFlags = Args.getLastArgValue(OPT_dwarf_debug_flags);
   Opts.RecordCommandLine = Args.getLastArgValue(OPT_record_command_line);
   Opts.MergeAllConstants = Args.hasArg(OPT_fmerge_all_constants);
-  Opts.NoCommon = Args.hasArg(OPT_fno_common);
+  Opts.NoCommon = !Args.hasArg(OPT_fcommon);
   Opts.NoInlineLineTables = Args.hasArg(OPT_gno_inline_line_tables);
   Opts.NoImplicitFloat = Args.hasArg(OPT_no_implicit_float);
   Opts.OptimizeSize = getOptimizationLevelSize(Args);