[clang] [Driver] Link Flang runtime on Solaris (PR #65644)

[Brad Smith via cfe-commits]

brad0 wrote:

Because of where the chunk is being added in the Solaris ToolChain (and what I had in my tree for *BSD's) it is checking for the ```nostdlib, nodefaultlibs, or r``` flags, where as the Gnu path does not. I just want to make sure the behavior is consistent.

tools::gnutools::Linker::ConstructJob

```
  if (D.CCCIsCXX() &&
      !Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
                   options::OPT_r)) {
    if (ToolChain.ShouldLinkCXXStdlib(Args)) {
      bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
                                 !Args.hasArg(options::OPT_static);
      if (OnlyLibstdcxxStatic)
        CmdArgs.push_back("-Bstatic");
      ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
      if (OnlyLibstdcxxStatic)
        CmdArgs.push_back("-Bdynamic");
    }
    CmdArgs.push_back("-lm");
  }

  // Silence warnings when linking C code with a C++ '-stdlib' argument.
  Args.ClaimAllArgs(options::OPT_stdlib_EQ);

  // Additional linker set-up and flags for Fortran. This is required in order
  // to generate executables. As Fortran runtime depends on the C runtime,
  // these dependencies need to be listed before the C runtime below (i.e.
  // AddRuntTimeLibs).
  if (D.IsFlangMode()) {
    addFortranRuntimeLibraryPath(ToolChain, Args, CmdArgs);
    addFortranRuntimeLibs(ToolChain, CmdArgs);
    CmdArgs.push_back("-lm");
  }
```

solaris::Linker::ConstructJob

```
  if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
                   options::OPT_r)) {
    if (D.CCCIsCXX()) {
      if (getToolChain().ShouldLinkCXXStdlib(Args))
        getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
      CmdArgs.push_back("-lm");
    }
    // Additional linker set-up and flags for Fortran. This is required in order
    // to generate executables. As Fortran runtime depends on the C runtime,
    // these dependencies need to be listed before the C runtime below.
    if (D.IsFlangMode()) {
      addFortranRuntimeLibraryPath(getToolChain(), Args, CmdArgs);
      addFortranRuntimeLibs(getToolChain(), CmdArgs);
      CmdArgs.push_back("-lm");
    }
```

https://github.com/llvm/llvm-project/pull/65644