[clang] clang_EvalResult_getAsCXString impl (PR #134551)

[Damian Andrei via cfe-commits]

================
@@ -52,6 +54,7 @@ typedef struct {
  * to `std::string::c_str()`.
  */
 CINDEX_LINKAGE const char *clang_getCString(CXString string);
+CINDEX_LINKAGE const char *clang_getCString2(CXString string, size_t *length);
----------------
xTachyon wrote:

I tried to find a macro that wraps _Nonnull to use here, but I couldn't find it.

https://github.com/llvm/llvm-project/pull/134551