[mlir][python][cmake] Allows for specifying NB_DOMAIN in `add_mlir_…

…python_extension` (llvm#122865)

This PR allows the users to specify the `NB_DOMAIN` for
`add_mlir_python_extension`. This allows users to avoid nanobind domain
conflicts, when python bindings from multiple `mlir` projects were
imported.
(https://nanobind.readthedocs.io/en/latest/faq.html#how-can-i-avoid-conflicts-with-other-projects-using-nanobind)

mlir/CMakeLists.txt

@@ -174,6 +174,8 @@ configure_file(
 # disable all package setup and control it themselves.
 #-------------------------------------------------------------------------------
 
+set(MLIR_BINDINGS_PYTHON_NB_DOMAIN "mlir"
+  CACHE STRING "nanobind domain for MLIR python bindings.")
 set(MLIR_ENABLE_BINDINGS_PYTHON 0 CACHE BOOL
        "Enables building of Python bindings.")
 set(MLIR_DETECT_PYTHON_ENV_PRIME_SEARCH 1 CACHE BOOL

mlir/cmake/modules/AddMLIRPython.cmake

@@ -667,7 +667,7 @@ function(add_mlir_python_extension libname extname)
     )
   elseif(ARG_PYTHON_BINDINGS_LIBRARY STREQUAL "nanobind")
     nanobind_add_module(${libname}
-      NB_DOMAIN mlir
+      NB_DOMAIN ${MLIR_BINDINGS_PYTHON_NB_DOMAIN}
       FREE_THREADED
       ${ARG_SOURCES}
     )