[lld] [ELF] Implement -z dynamic-undefined-weak (PR #143831)

[Peter Smith via llvm-commits]

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@@ -47,7 +47,8 @@
 # ERR9: error: cannot open output file utput=/no/such/file
 
 # RUN: ld.lld %t -z foo -o /dev/null 2>&1 | FileCheck -check-prefix=ERR10 %s --implicit-check-not=warning:
-# RUN: ld.lld %t -z foo -z rel -z rela -z max-page-size=1 -z common-page-size=1 -o /dev/null --version 2>&1 | \
+# RUN: ld.lld %t -z foo -z rel -z rela -z max-page-size=1 -z common-page-size=1 -z dynamic-undefined-weak \
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smithp35 wrote:

Just to check this is testing that the later `-z nodynamic-undefined-weak` overrides `-z nodynamic-undefined-weak`?

https://github.com/llvm/llvm-project/pull/143831