[flang-commits] [flang] [flang][OpenMP] Use `llvm::enumerate` in few places, NFC (PR #76095)

[Kiran Chandramohan via flang-commits]

kiranchandramohan wrote:

@kparzysz there are still some failures. https://lab.llvm.org/buildbot/#/builders/268/builds/4876
```
FAILED: tools/flang/lib/Lower/CMakeFiles/obj.FortranLower.dir/OpenMP.cpp.o 
/usr/local/bin/c++ -DFLANG_INCLUDE_TESTS=1 -DFLANG_LITTLE_ENDIAN=1 -DGTEST_HAS_RTTI=0 -D_DEBUG -D_GLIBCXX_ASSERTIONS -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/flang/lib/Lower -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/lib/Lower -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/flang/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/include -I/home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/../mlir/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/mlir/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/tools/clang/include -isystem /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/llvm/../clang/include -stdlib=libc++ -fPIC -fno-semantic-interposition -fvisibility-inlines-hidden -Werror=date-time -Werror=unguarded-availability-new -Wall -Wextra -Wno-unused-parameter -Wwrite-strings -Wcast-qual -Wmissing-field-initializers -pedantic -Wno-long-long -Wc++98-compat-extra-semi -Wimplicit-fallthrough -Wcovered-switch-default -Wno-noexcept-type -Wnon-virtual-dtor -Wdelete-non-virtual-dtor -Wsuggest-override -Wstring-conversion -Wmisleading-indentation -Wctad-maybe-unsupported -fdiagnostics-color -ffunction-sections -fdata-sections -Werror -Wno-deprecated-copy -Wno-string-conversion -Wno-ctad-maybe-unsupported -Wno-unused-command-line-argument -Wstring-conversion           -Wcovered-switch-default -Wno-nested-anon-types -O3 -DNDEBUG  -fno-exceptions -funwind-tables -fno-rtti -UNDEBUG -std=c++17 -MD -MT tools/flang/lib/Lower/CMakeFiles/obj.FortranLower.dir/OpenMP.cpp.o -MF tools/flang/lib/Lower/CMakeFiles/obj.FortranLower.dir/OpenMP.cpp.o.d -o tools/flang/lib/Lower/CMakeFiles/obj.FortranLower.dir/OpenMP.cpp.o -c /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/lib/Lower/OpenMP.cpp
../llvm-project/flang/lib/Lower/OpenMP.cpp:2203:20: error: captured structured bindings are a C++20 extension [-Werror,-Wc++20-extensions]
 2203 |                   *argSymbol,
      |                    ^
../llvm-project/flang/lib/Lower/OpenMP.cpp:2193:24: note: 'argSymbol' declared here
 2193 |   for (auto [argIndex, argSymbol] : llvm::enumerate(useDeviceSymbols)) {
      |                        ^
1 error generated.
ninja: build stopped: subcommand failed.
```

https://github.com/llvm/llvm-project/pull/76095