[llvm] [llvm-dlltool] Implement the --identify option (PR #127465)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-nvptx-nvidia-ubuntu` running on `as-builder-7` while building `llvm` at step 5 "build-unified-tree".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/180/builds/13316

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 5 (build-unified-tree) failure: build (failure)
...
65.276 [341/18/2357] Building X86GenInstrMapping.inc...
65.357 [341/17/2358] Building X86GenCallingConv.inc...
65.403 [341/16/2359] Building X86GenAsmWriter1.inc...
65.577 [341/15/2360] Building X86GenAsmMatcher.inc...
65.654 [341/14/2361] Building X86GenDisassemblerTables.inc...
66.949 [341/13/2362] Building X86GenGlobalISel.inc...
67.987 [341/12/2363] Building X86GenDAGISel.inc...
69.303 [341/11/2364] Building X86GenExegesis.inc...
70.782 [341/10/2365] Building CXX object lib/ToolDrivers/llvm-dlltool/CMakeFiles/LLVMDlltoolDriver.dir/DlltoolDriver.cpp.o
71.002 [340/10/2366] Linking CXX shared library lib/libLLVMDlltoolDriver.so.21.0git
FAILED: lib/libLLVMDlltoolDriver.so.21.0git 
: && /usr/bin/c++ -fPIC -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -fno-lifetime-dse -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wno-missing-field-initializers -pedantic -Wno-long-long -Wimplicit-fallthrough -Wno-uninitialized -Wno-nonnull -Wno-class-memaccess -Wno-redundant-move -Wno-pessimizing-move -Wno-noexcept-type -Wdelete-non-virtual-dtor -Wsuggest-override -Wno-comment -Wno-misleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -O3 -DNDEBUG  -Wl,-z,defs -Wl,-z,nodelete -fuse-ld=gold   -Wl,--gc-sections -shared -Wl,-soname,libLLVMDlltoolDriver.so.21.0git -o lib/libLLVMDlltoolDriver.so.21.0git lib/ToolDrivers/llvm-dlltool/CMakeFiles/LLVMDlltoolDriver.dir/DlltoolDriver.cpp.o  -Wl,-rpath,"\$ORIGIN/../lib:/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/build/lib:"  lib/libLLVMObject.so.21.0git  lib/libLLVMOption.so.21.0git  lib/libLLVMTargetParser.so.21.0git  lib/libLLVMSupport.so.21.0git  -Wl,-rpath-link,/home/buildbot/worker/as-builder-7/ramdisk/llvm-nvptx-nvidia-ubuntu/build/lib && :
lib/ToolDrivers/llvm-dlltool/CMakeFiles/LLVMDlltoolDriver.dir/DlltoolDriver.cpp.o:DlltoolDriver.cpp:function (anonymous namespace)::doIdentify(llvm::StringRef, bool): error: undefined reference to 'llvm::identify_magic(llvm::StringRef)'
lib/ToolDrivers/llvm-dlltool/CMakeFiles/LLVMDlltoolDriver.dir/DlltoolDriver.cpp.o:DlltoolDriver.cpp:function (anonymous namespace)::doIdentify(llvm::StringRef, bool): error: undefined reference to 'llvm::identify_magic(llvm::StringRef)'
collect2: error: ld returned 1 exit status
71.131 [340/9/2367] Building X86GenRegisterInfo.inc...
71.441 [340/8/2368] Building X86GenRegisterBank.inc...
72.331 [340/7/2369] Building NVPTXGenDAGISel.inc...
73.151 [340/6/2370] Building X86GenMnemonicTables.inc...
73.329 [340/5/2371] Building X86GenAsmWriter.inc...
73.646 [340/4/2372] Building X86GenFoldTables.inc...
75.128 [340/3/2373] Building X86GenFastISel.inc...
76.467 [340/2/2374] Building X86GenSubtargetInfo.inc...
78.456 [340/1/2375] Building X86GenInstrInfo.inc...
ninja: build stopped: subcommand failed.

```

</details>

https://github.com/llvm/llvm-project/pull/127465