[llvm] [cross-project-tests] Add `has-gdb` LIT feature (PR #188780)

[Jonas Devlieghere via llvm-commits]

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@@ -1,10 +1,16 @@
+// REQUIRES: system-darwin || has-gdb
+//
 // This ensures that DW_OP_deref is inserted when necessary, such as when NRVO
 // of a string object occurs in C++.
 //
-// RUN: %clangxx -O0 -fno-exceptions %target_itanium_abi_host_triple %s -o %t.out -g
+// RUN: %clangxx -O0 -fno-exceptions %target_itanium_abi_host_triple %s \
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JDevlieghere wrote:

This seems to have broken the nrvo-string.cpp test

https://github.com/llvm/llvm-project/pull/188780