[Clang][CMake][MSVC] Install PDBs alongside executables (llvm#126675)

* Follows up on llvm#120683
enabling PDBs for `clang`.

Author: mayanez

clang/cmake/modules/AddClang.cmake

@@ -138,6 +138,10 @@ macro(add_clang_library name)
           ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX}
           RUNTIME DESTINATION "${CMAKE_INSTALL_BINDIR}")
 
+        if (LLVM_ENABLE_PDB)
+          install(FILES $<TARGET_PDB_FILE:${name}> DESTINATION "${CMAKE_INSTALL_BINDIR}" COMPONENT ${name} OPTIONAL)
+        endif()
+
         if (NOT LLVM_ENABLE_IDE)
           add_llvm_install_targets(install-${lib}
                                    DEPENDS ${lib}