[llvm] [NFC]Make file-local cl::opt global variables static (PR #126486)

[Matt Arsenault via llvm-commits]

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@@ -121,8 +121,8 @@ cl::list<std::string> SafeToolArgv("safe-tool-args", cl::Positional,
                                    cl::desc("<safe-tool arguments>..."),
                                    cl::PositionalEatsArgs);
 
-cl::opt<std::string> CCBinary("gcc", cl::init(""),
-                              cl::desc("The gcc binary to use."));
+static cl::opt<std::string> CCBinary("gcc", cl::init(""),
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arsenm wrote:

style guide says to prefer static 

https://github.com/llvm/llvm-project/pull/126486