BUG, BLD: Generate the main dispatcher config header into the build dir

  The new path becomes `build/src.*/numpy/distutils/include/npy_cpu_dispatch_config.h`
  instead of `numpy/core/src/common/_cpu_dispatch.h`.

  The new path allows other projects to re-use the CPU dispatcher
  once we decide to expose the following headers:
    - `numpy/core/src/common/npy_cpu_dispatch.h`
    - `numpy/core/src/common/npy_cpu_features.h`

1 files changed, 17 insertions, 15 deletions

diff --git a/numpy/distutils/ccompiler_opt.py b/numpy/distutils/ccompiler_opt.py
index ecf5172cc..39c08d36b 100644
--- a/numpy/distutils/ccompiler_opt.py
+++ b/numpy/distutils/ccompiler_opt.py
@@ -2240,6 +2240,14 @@ class CCompilerOpt(_Config, _Distutils, _Cache, _CCompiler, _Feature, _Parse):
         baseline_len = len(baseline_names)
         dispatch_len = len(dispatch_names)
 
+        header_dir = os.path.dirname(header_path)
+        if not os.path.exists(header_dir):
+            self.dist_log(
+                f"dispatch header dir {header_dir} isn't exist, creating it",
+                stderr=True
+            )
+            os.makedirs(header_dir)
+
         with open(header_path, 'w') as f:
             baseline_calls = ' \\\n'.join([
                 (
@@ -2504,30 +2512,24 @@ class CCompilerOpt(_Config, _Distutils, _Cache, _CCompiler, _Feature, _Parse):
             ))
         return False
 
-def new_ccompiler_opt(compiler, **kwargs):
+def new_ccompiler_opt(compiler, dispatch_hpath, **kwargs):
     """
     Create a new instance of 'CCompilerOpt' and generate the dispatch header
-    inside NumPy source dir.
+    which containing all definitions and headers of instruction-sets for
+    the enabled CPU baseline and dispatch-able features.
 
     Parameters
     ----------
-    'compiler' : CCompiler instance
-    '**kwargs': passed as-is to `CCompilerOpt(...)`
+    compiler : CCompiler instance
+    dispatch_hpath : str
+        path of the dispatch header
 
+    **kwargs: passed as-is to `CCompilerOpt(...)`
     Returns
     -------
     new instance of CCompilerOpt
     """
     opt = CCompilerOpt(compiler, **kwargs)
-    npy_path = os.path.abspath(os.path.join(os.path.dirname(__file__), ".."))
-    header_dir = os.path.join(npy_path, *("core/src/common".split("/")))
-    header_path = os.path.join(header_dir, "_cpu_dispatch.h")
-    if not os.path.exists(header_path) or not opt.is_cached():
-        if not os.path.exists(header_dir):
-            opt.dist_log(
-                "dispatch header dir '%s' isn't exist, creating it" % header_dir,
-                stderr=True
-            )
-            os.makedirs(header_dir)
-        opt.generate_dispatch_header(header_path)
+    if not os.path.exists(dispatch_hpath) or not opt.is_cached():
+        opt.generate_dispatch_header(dispatch_hpath)
     return opt