diff --git a/Lib/distutils/sysconfig.py b/Lib/distutils/sysconfig.py
index daa4dc7..250ef38 100644
--- a/Lib/distutils/sysconfig.py
+++ b/Lib/distutils/sysconfig.py
@@ -37,6 +37,11 @@
     project_base = os.path.abspath(os.path.join(project_base, os.path.pardir,
                                                 os.path.pardir))
 
+# set for cross builds
+if "_PYTHON_PROJECT_BASE" in os.environ:
+    # this is the build directory, at least for posix
+    project_base = os.path.normpath(os.environ["_PYTHON_PROJECT_BASE"])
+
 # python_build: (Boolean) if true, we're either building Python or
 # building an extension with an un-installed Python, so we use
 # different (hard-wired) directories.
@@ -230,7 +235,7 @@
 def get_makefile_filename():
     """Return full pathname of installed Makefile from the Python build."""
     if python_build:
-        return os.path.join(os.path.dirname(sys.executable), "Makefile")
+        return os.path.join(project_base, "Makefile")
     lib_dir = get_python_lib(plat_specific=1, standard_lib=1)
     return os.path.join(lib_dir, "config", "Makefile")
 
diff --git a/Lib/distutils/util.py b/Lib/distutils/util.py
index 5279411..ea6ed8a 100644
--- a/Lib/distutils/util.py
+++ b/Lib/distutils/util.py
@@ -51,6 +51,10 @@
             return 'win-ia64'
         return sys.platform
 
+    # Set for cross builds explicitly
+    if "_PYTHON_HOST_PLATFORM" in os.environ:
+        return os.environ["_PYTHON_HOST_PLATFORM"]
+
     if os.name != "posix" or not hasattr(os, 'uname'):
         # XXX what about the architecture? NT is Intel or Alpha,
         # Mac OS is M68k or PPC, etc.
diff --git a/Lib/plat-generic/regen b/Lib/plat-generic/regen
index a20cdc1..c96167d 100755
--- a/Lib/plat-generic/regen
+++ b/Lib/plat-generic/regen
@@ -1,3 +1,3 @@
 #! /bin/sh
 set -v
-python$EXE ../../Tools/scripts/h2py.py -i '(u_long)' /usr/include/netinet/in.h
+eval $PYTHON_FOR_BUILD ../../Tools/scripts/h2py.py -i "'(u_long)'" /usr/include/netinet/in.h
diff --git a/Lib/sysconfig.py b/Lib/sysconfig.py
index 9442d39..d74ca39 100644
--- a/Lib/sysconfig.py
+++ b/Lib/sysconfig.py
@@ -116,6 +116,10 @@
 if os.name == "nt" and "\\pcbuild\\amd64" in _PROJECT_BASE[-14:].lower():
     _PROJECT_BASE = _safe_realpath(os.path.join(_PROJECT_BASE, pardir, pardir))
 
+# set for cross builds
+if "_PYTHON_PROJECT_BASE" in os.environ:
+    # the build directory for posix builds
+    _PROJECT_BASE = os.path.normpath(os.path.abspath("."))
 def is_python_build():
     for fn in ("Setup.dist", "Setup.local"):
         if os.path.isfile(os.path.join(_PROJECT_BASE, "Modules", fn)):
@@ -507,6 +511,10 @@
             return 'win-ia64'
         return sys.platform
 
+    # Set for cross builds explicitly
+    if "_PYTHON_HOST_PLATFORM" in os.environ:
+        return os.environ["_PYTHON_HOST_PLATFORM"]
+
     if os.name != "posix" or not hasattr(os, 'uname'):
         # XXX what about the architecture? NT is Intel or Alpha,
         # Mac OS is M68k or PPC, etc.