Fix building aganst system Qhull.

Author: QuLogic

setup.py

@@ -47,8 +47,7 @@
 from distutils.dist import Distribution
 
 import setupext
-from setupext import (
-    get_and_extract_tarball, print_raw, print_status, LOCAL_QHULL_VERSION)
+from setupext import print_raw, print_status
 
 # Get the version from versioneer
 import versioneer
@@ -61,6 +60,7 @@
     setupext.Python(),
     setupext.Platform(),
     setupext.FreeType(),
+    setupext.Qhull(),
     setupext.SampleData(),
     setupext.Tests(),
     setupext.BackendMacOSX(),
@@ -86,18 +86,8 @@ def __init__(self, dist):
               "'python setup.py test'. Please run 'pytest'.")
 
 
-def _download_qhull():
-    toplevel = get_and_extract_tarball(
-        urls=["http://www.qhull.org/download/qhull-2020-src-8.0.2.tgz"],
-        sha="b5c2d7eb833278881b952c8a52d20179eab87766b00b865000469a45c1838b7e",
-        dirname=f"qhull-{LOCAL_QHULL_VERSION}",
-    )
-    shutil.copyfile(toplevel / "COPYING.txt", "LICENSE/LICENSE_QHULL")
-
-
 class BuildExtraLibraries(BuildExtCommand):
     def finalize_options(self):
-        _download_qhull()
         self.distribution.ext_modules[:] = [
             ext
             for package in good_packages

setupext.py

@@ -441,7 +441,7 @@ def get_extensions(self):
             "matplotlib._qhull", ["src/qhull_wrap.c"],
             define_macros=[("MPL_DEVNULL", os.devnull)])
         add_numpy_flags(ext)
-        add_qhull_flags(ext)
+        Qhull.add_flags(ext)
         yield ext
         # tkagg
         ext = Extension(
@@ -550,17 +550,6 @@ def add_libagg_flags_and_sources(ext):
         os.path.join("extern", "agg24-svn", "src", x) for x in agg_sources)
 
 
-def add_qhull_flags(ext):
-    if options.get("system_qhull"):
-        ext.libraries.append("qhull")
-    else:
-        qhull_path = Path(f'build/qhull-{LOCAL_QHULL_VERSION}/src')
-        ext.include_dirs.insert(0, str(qhull_path))
-        ext.sources.extend(map(str, sorted(qhull_path.glob('libqhull_r/*.c'))))
-        if sysconfig.get_config_var("LIBM") == "-lm":
-            ext.libraries.extend("m")
-
-
 # First compile checkdep_freetype2.c, which aborts the compilation either
 # with "foo.h: No such file or directory" if the header is not found, or an
 # appropriate error message if the header indicates a too-old version.
@@ -687,6 +676,36 @@ def do_custom_build(self, env):
             shutil.copy2(lib_path, src_path / "objs/.libs/libfreetype.lib")
 
 
+class Qhull(SetupPackage):
+    name = "qhull"
+    _extensions_to_update = []
+
+    @classmethod
+    def add_flags(cls, ext):
+        if options.get("system_qhull"):
+            ext.libraries.append("qhull_r")
+        else:
+            cls._extensions_to_update.append(ext)
+
+    def do_custom_build(self, env):
+        if options.get('system_qhull'):
+            return
+
+        toplevel = get_and_extract_tarball(
+            urls=["http://www.qhull.org/download/qhull-2020-src-8.0.2.tgz"],
+            sha="b5c2d7eb833278881b952c8a52d20179eab87766b00b865000469a45c1838b7e",
+            dirname=f"qhull-{LOCAL_QHULL_VERSION}",
+        )
+        shutil.copyfile(toplevel / "COPYING.txt", "LICENSE/LICENSE_QHULL")
+
+        for ext in self._extensions_to_update:
+            qhull_path = Path(f'build/qhull-{LOCAL_QHULL_VERSION}/src')
+            ext.include_dirs.insert(0, str(qhull_path))
+            ext.sources.extend(map(str, sorted(qhull_path.glob('libqhull_r/*.c'))))
+            if sysconfig.get_config_var("LIBM") == "-lm":
+                ext.libraries.extend("m")
+
+
 class BackendMacOSX(OptionalPackage):
     config_category = 'gui_support'
     name = 'macosx'