[clang] Disable -fdollars-in-identifiers by default (PR #135407)

[Aaron Ballman via cfe-commits]

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@@ -7,7 +7,7 @@
 #define foo`bar   /* expected-error {{whitespace required after macro name}} */
 #define foo2!bar  /* expected-warning {{whitespace recommended after macro name}} */
 
-#define foo3$bar  /* expected-error {{'$' in identifier}} */
+#define foo3$bar  /* expected-error {{whitespace required after macro name}} */
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AaronBallman wrote:

In `-pedentic-errors` mode before the patch, dollar signs in identifiers are recognized and so we get `#` `define` `<identifier>` and issue the pedantic diagnostic. With the patch, dollar signs in identifiers are not recognized at all and so we get `#` `define` `foo` `$` `bar` which has no whitespace between the macro name and its replacement list.

https://github.com/llvm/llvm-project/pull/135407