Merge pull request matplotlib#21279 from QuLogic/fix-freetype-wheel

Fix freetype wheel building

Author: jklymak

setupext.py

@@ -605,22 +605,27 @@ def do_custom_build(self, env):
         if (src_path / 'objs' / '.libs' / libfreetype).is_file():
             return  # Bail out because we have already built FreeType.
 
-        cc = get_ccompiler()
-
         print(f"Building freetype in {src_path}")
         if sys.platform != 'win32':  # compilation on non-windows
             env = {
                 **env,
-                "CC": (shlex.join(cc.compiler) if sys.version_info >= (3, 8)
-                       else " ".join(shlex.quote(x) for x in cc.compiler)),
-                "CFLAGS": "{} -fPIC".format(env.get("CFLAGS", "")),
+                **{
+                    var: value
+                    for var, value in sysconfig.get_config_vars().items()
+                    if var in {"CC", "CFLAGS", "CXX", "CXXFLAGS", "LD",
+                               "LDFLAGS"}
+                },
             }
-            subprocess.check_call(
-                ["./configure", "--with-zlib=no", "--with-bzip2=no",
-                 "--with-png=no", "--with-harfbuzz=no", "--enable-static",
-                 "--disable-shared",
-                 "--host=" + sysconfig.get_config_var('BUILD_GNU_TYPE')],
-                env=env, cwd=src_path)
+            env["CFLAGS"] = env.get("CFLAGS", "") + " -fPIC"
+            configure = [
+                "./configure", "--with-zlib=no", "--with-bzip2=no",
+                "--with-png=no", "--with-harfbuzz=no", "--enable-static",
+                "--disable-shared"
+            ]
+            host = sysconfig.get_config_var('BUILD_GNU_TYPE')
+            if host is not None:  # May be unset on PyPy.
+                configure.append(f"--host={host}")
+            subprocess.check_call(configure, env=env, cwd=src_path)
             if 'GNUMAKE' in env:
                 make = env['GNUMAKE']
             elif 'MAKE' in env:
@@ -668,6 +673,7 @@ def do_custom_build(self, env):
                 f.truncate()
                 f.write(vcxproj)
 
+            cc = get_ccompiler()
             cc.initialize()  # Get msbuild in the %PATH% of cc.spawn.
             cc.spawn(["msbuild", str(sln_path),
                       "/t:Clean;Build",