Compile with -j flag

[ReubenVandezande]

I have a large number of files to compile, is there an option to enable parallel compilation with -j? If not, could you add one?

[ReubenVandezande]

Built and compiled with this successfully.

diff --git a/src/hatch_cython/config/config.py b/src/hatch_cython/config/config.py
index a0c0160..59fed52 100644
--- a/src/hatch_cython/config/config.py
+++ b/src/hatch_cython/config/config.py
@@ -34,6 +34,7 @@ __known__ = frozenset(
         "define_macros",
         "compiled_sdist",
         "extra_link_args",
+        "compile_parallel",
         "cythonize_kwargs",
     )
 )
@@ -145,6 +146,7 @@ class Config:
     directives: dict = field(default_factory=lambda: DIRECTIVES)
     compile_args: ListedArgs = field(default_factory=get_default_compile)
     compile_kwargs: dict = field(default_factory=dict)
+    compile_parallel: int = field(default=1)
     cythonize_kwargs: dict = field(default_factory=dict)
     extra_link_args: ListedArgs = field(default_factory=get_default_link)
     compiled_sdist: bool = field(default=False)
diff --git a/src/hatch_cython/plugin.py b/src/hatch_cython/plugin.py
index 43c3737..4615f83 100644
--- a/src/hatch_cython/plugin.py
+++ b/src/hatch_cython/plugin.py
@@ -263,6 +263,10 @@ class CythonBuildHook(BuildHookInterface):
             self.precompiled_extensions.add(".cpp")
         return config
 
+    @property
+    def compile_parallel(self) -> int:
+        return self.options.compile_parallel    
+
     @property
     def sdist(self):
         return self.target_name == "sdist"
@@ -294,19 +298,24 @@ class CythonBuildHook(BuildHookInterface):
                 f.write(setup)
 
             self.options.validate_include_opts()
-
+            command = [
+                sys.executable,
+                setup_file,
+                "build_ext",
+                "--inplace",
+                "--verbose",
+                "--build-lib",
+                shared_temp_build_dir,
+                "--build-temp",
+                temp_build_dir,
+            ]
+            
+            if self.compile_parallel > 1:
+                self.app.display_info(f"Compiling in parallel ({self.compile_parallel})")
+                command.extend(["-j", str(self.compile_parallel)])
+            
             process = subprocess.run(  # noqa: PLW1510
-                [  # noqa: S603
-                    sys.executable,
-                    setup_file,
-                    "build_ext",
-                    "--inplace",
-                    "--verbose",
-                    "--build-lib",
-                    shared_temp_build_dir,
-                    "--build-temp",
-                    temp_build_dir,
-                ],
+                command,   
                 stdout=subprocess.PIPE,
                 stderr=subprocess.STDOUT,
                 env=self.options.envflags.env,