diff --git a/Makefile.envs b/Makefile.envs
index ceb4ab25c..49e91dbb3 100644
--- a/Makefile.envs
+++ b/Makefile.envs
@@ -4,6 +4,7 @@ export PYVERSION ?= 3.10.2
 export PYODIDE_EMSCRIPTEN_VERSION ?= 2.0.27
 
 export PLATFORM_TRIPLET=wasm32-emscripten
+export SYSCONFIG_NAME=_sysconfigdata__emscripten_$(PLATFORM_TRIPLET)
 
 # BASH_ENV tells bash to run pyodide_env.sh on startup, which sets various
 # environment variables. The next line instructs make to use bash to run each
diff --git a/cpython/Makefile b/cpython/Makefile
index 3e096282c..da8a5c6bc 100644
--- a/cpython/Makefile
+++ b/cpython/Makefile
@@ -10,7 +10,6 @@ INSTALL=$(ROOT)/installs/python-$(PYVERSION)
 TARBALL=$(ROOT)/downloads/Python-$(PYVERSION).tgz
 URL=https://www.python.org/ftp/python/$(PYVERSION)/Python-$(PYVERSION).tgz
 LIB=libpython$(PYMAJOR).$(PYMINOR).a
-SYSCONFIG_NAME=_sysconfigdata__emscripten_$(PLATFORM_TRIPLET)
 
 ZLIBVERSION=1.2.12
 ZLIBTARBALL=$(ROOT)/downloads/zlib-$(ZLIBVERSION).tar.gz
@@ -43,10 +42,15 @@ $(INSTALL)/lib/$(LIB): $(BUILD)/$(LIB) remove_modules.txt
 	# Generate sysconfigdata. It outputs into a subfolder of build/, and
 	# the subfolder is written to pybuilddir.txt.
 	_PYTHON_SYSCONFIGDATA_NAME=$(SYSCONFIG_NAME) _PYTHON_PROJECT_BASE=$(BUILD) $(HOSTPYTHON) -m sysconfig --generate-posix-vars
-	mv `cat pybuilddir.txt`/$(SYSCONFIG_NAME).py $(INSTALL)/lib/python$(PYMAJOR).$(PYMINOR)/
-	rmdir `cat pybuilddir.txt`
-	rm pybuilddir.txt
+
+	$(eval PYBUILDDIR=`cat pybuilddir.txt`)
+	PYTHONPATH=$(PYBUILDDIR) python adjust_sysconfig.py
+	cp $(PYBUILDDIR)/$(SYSCONFIG_NAME).py $(INSTALL)/lib/python$(PYMAJOR).$(PYMINOR)/
+	mkdir -p $(INSTALL)/sysconfigdata/
+	cp $(PYBUILDDIR)/$(SYSCONFIG_NAME).py $(INSTALL)/sysconfigdata/
 	cd $(INSTALL)/lib/python$(PYMAJOR).$(PYMINOR)/ && rm -rf `cat $(ROOT)/remove_modules.txt`
+	rm -rf $(PYBUILDDIR)
+	rm pybuilddir.txt
 
 
 clean:
diff --git a/cpython/adjust_sysconfig.py b/cpython/adjust_sysconfig.py
new file mode 100644
index 000000000..511fffa32
--- /dev/null
+++ b/cpython/adjust_sysconfig.py
@@ -0,0 +1,36 @@
+import os
+import pprint
+
+
+def load_sysconfig(sysconfig_name: str):
+    _temp = __import__(sysconfig_name, globals(), locals(), ["build_time_vars"], 0)
+    config_vars = _temp.build_time_vars
+    return config_vars, _temp.__file__
+
+
+def write_sysconfig(destfile: str, config_vars: dict[str, str]):
+    with open(destfile, "w", encoding="utf8") as f:
+        f.write(
+            "# system configuration generated and used by" " the sysconfig module\n"
+        )
+        f.write("build_time_vars = ")
+        pprint.pprint(config_vars, stream=f)
+
+
+def adjust_sysconfig(config_vars: dict[str, str]):
+    config_vars.update(
+        CC="cc",
+        MAINCC="cc",
+        LDSHARED="cc",
+        LINKCC="cc",
+        BLDSHARED="cc",
+        CXX="c++",
+        LDCXXSHARED="c++",
+    )
+
+
+if __name__ == "__main__":
+    sysconfig_name = os.environ["SYSCONFIG_NAME"]
+    config_vars, file = load_sysconfig(sysconfig_name)
+    adjust_sysconfig(config_vars)
+    write_sysconfig(file, config_vars)
diff --git a/docs/project/changelog.md b/docs/project/changelog.md
index 5ad61a2f4..cc367f17b 100644
--- a/docs/project/changelog.md
+++ b/docs/project/changelog.md
@@ -109,9 +109,14 @@ substitutions:
   wheels are distributed outside of the main Pyodide distribution.
   {pr}`2610`
 
+- {{ Enhancement }} The build system now uses the sysconfigdata from the target
+  Python rather than the host Python.
+  {pr}`2516`
+
 ### REPL
 
-- {{ Enhancement }} Add a spinner while the REPL is loading {pr}`2635`
+- {{ Enhancement }} Add a spinner while the REPL is loading
+  {pr}`2635`
 
 ### micropip
 
diff --git a/packages/fpcast-test/fpcast-test/setup.py b/packages/fpcast-test/fpcast-test/setup.py
index 537d10aab..02550939d 100644
--- a/packages/fpcast-test/fpcast-test/setup.py
+++ b/packages/fpcast-test/fpcast-test/setup.py
@@ -1,5 +1,19 @@
+from sysconfig import get_config_var
+
 from setuptools import Extension, setup
 
+if get_config_var("SIZEOF_VOID_P") != 4:
+    # pyodide_build.pypabuild will run this three times, the first time it fails
+    # and the exception is caught but the second and third times it must
+    # succeed.
+    raise Exception(
+        """
+This should appear in the log exactly one time. If it appears more than once,
+the Pyodide build system has misconfigured sysconfigdata (and also the build
+will fail).
+"""
+    )
+
 setup(
     name="fpcast-test",
     version="0.1.1",
diff --git a/pyodide-build/pyodide_build/buildpkg.py b/pyodide-build/pyodide_build/buildpkg.py
index 52622d3e9..d9587825e 100755
--- a/pyodide-build/pyodide_build/buildpkg.py
+++ b/pyodide-build/pyodide_build/buildpkg.py
@@ -137,6 +137,7 @@ def get_bash_runner():
             "PYODIDE_PACKAGE_ABI",
             "HOSTINSTALLDIR",
             "TARGETINSTALLDIR",
+            "SYSCONFIG_NAME",
             "HOSTSITEPACKAGES",
             "PYMAJOR",
             "PYMINOR",
@@ -506,6 +507,7 @@ def package_wheel(
         raise Exception(
             f"Unexpected number of wheels {len(rest) + 1} when building {pkg_name}"
         )
+    print(f"Unpacking wheel to {str(wheel)}")
     unpack_wheel(wheel)
     wheel.unlink()
     name, ver, _ = wheel.name.split("-", 2)
@@ -518,7 +520,8 @@ def package_wheel(
 
     post = build_metadata.get("post")
     if post:
-        bash_runner.env.update({"PKGDIR": str(pkg_root)})
+        print("Running post script in ", str(Path.cwd().absolute()))
+        bash_runner.env.update({"PKGDIR": str(pkg_root), "WHEELDIR": str(wheel_dir)})
         result = bash_runner.run(post)
         if result.returncode != 0:
             print("ERROR: post failed")
diff --git a/pyodide-build/pyodide_build/pypabuild.py b/pyodide-build/pyodide_build/pypabuild.py
index a6fed86db..8572d56fc 100644
--- a/pyodide-build/pyodide_build/pypabuild.py
+++ b/pyodide-build/pyodide_build/pypabuild.py
@@ -1,5 +1,6 @@
 import contextlib
 import os
+import shutil
 import sys
 import traceback
 from itertools import chain
@@ -24,6 +25,11 @@ def symlink_unisolated_packages(env: IsolatedEnv) -> None:
     pyversion = get_pyversion()
     site_packages_path = f"lib/{pyversion}/site-packages"
     env_site_packages = Path(env.path) / site_packages_path  # type: ignore[attr-defined]
+    sysconfigdata_name = os.environ["SYSCONFIG_NAME"]
+    sysconfigdata_path = (
+        Path(os.environ["TARGETINSTALLDIR"]) / f"sysconfigdata/{sysconfigdata_name}.py"
+    )
+    shutil.copy(sysconfigdata_path, env_site_packages)
     host_site_packages = Path(get_hostsitepackages())
     for name in get_unisolated_packages():
         for path in chain(
diff --git a/pyodide-build/pyodide_build/pywasmcross.py b/pyodide-build/pyodide_build/pywasmcross.py
index 09c3e96d8..96ad0dafc 100755
--- a/pyodide-build/pyodide_build/pywasmcross.py
+++ b/pyodide-build/pyodide_build/pywasmcross.py
@@ -103,11 +103,13 @@ def compile(
     env = dict(env)
     SYMLINKDIR = symlink_dir()
     env["PATH"] = f"{SYMLINKDIR}:{env['PATH']}"
-    args["PYTHONPATH"] = sys.path
+    sysconfig_dir = Path(os.environ["TARGETINSTALLDIR"]) / "sysconfigdata"
+    args["PYTHONPATH"] = sys.path + [str(sysconfig_dir)]
     args["orig__name__"] = __name__
     make_command_wrapper_symlinks(env)
     env["PYWASMCROSS_ARGS"] = json.dumps(args)
     env["_PYTHON_HOST_PLATFORM"] = common.platform()
+    env["_PYTHON_SYSCONFIGDATA_NAME"] = os.environ["SYSCONFIG_NAME"]
 
     from pyodide_build.pypabuild import build