BLD: only compile fixed_interpolator.cpp once

Avoid a race condition on fixed_interpolator.o during parallel builds by
building it only once and storing it in a static library.

Hopefully fixes yt-project#4278.

setup.py

@@ -112,7 +112,10 @@ def has_ext_modules(self):
         {
             "sources": ["yt/utilities/lib/fixed_interpolator.cpp"],
             "include_dirs": clib_include_dirs,
+<<<<<<< HEAD
             "define_macros": NUMPY_MACROS,
+=======
+>>>>>>> 8a11260ad (BLD: only compile fixed_interpolator.cpp once)
         },
     )
 

setupext.py

@@ -370,7 +370,11 @@ def _compile(
 
 
 def get_python_include_dirs():
+<<<<<<< HEAD
     """Extracted from distutils.command.build_ext.build_ext.finalize_options(),
+=======
+    """Extracted from distutils.command.build_ext.build_ext#finalize_options(),
+>>>>>>> 8a11260ad (BLD: only compile fixed_interpolator.cpp once)
     https://github.com/python/cpython/blob/812245ecce2d8344c3748228047bab456816180a/Lib/distutils/command/build_ext.py#L148-L167
     """
     include_dirs = []
@@ -394,13 +398,16 @@ def get_python_include_dirs():
     return include_dirs
 
 
+<<<<<<< HEAD
 NUMPY_MACROS = [
     ("NPY_NO_DEPRECATED_API", "NPY_1_7_API_VERSION"),
     # keep in sync with runtime requirements (pyproject.toml)
     ("NPY_TARGET_VERSION", "NPY_1_19_API_VERSION"),
 ]
 
 
+=======
+>>>>>>> 8a11260ad (BLD: only compile fixed_interpolator.cpp once)
 def create_build_ext(lib_exts, cythonize_aliases):
     class build_ext(_build_ext):
         # subclass setuptools extension builder to avoid importing cython and numpy

yt/utilities/lib/grid_traversal.pyx

@@ -1,5 +1,9 @@
 # distutils: include_dirs = LIB_DIR
+<<<<<<< HEAD
 # distutils: libraries = STD_LIBS
+=======
+# distutils: libraries = STD_LIBS FIXED_INTERP
+>>>>>>> 8a11260ad (BLD: only compile fixed_interpolator.cpp once)
 # distutils: language = c++
 # distutils: extra_compile_args = CPP14_FLAG
 # distutils: extra_link_args = CPP14_FLAG