setup.py supports building Python with an OS X SDK to allow building Python executables and libraries that will run on multiple versions of OS X.  There is an error in the SDK support code in detect_modules() for building the _sqlite3 extension that has the effect of incorrectly using header files for libsqlite3 from the build system's installed /usr/include rather than the selected SDK's usr/include. Depending on which SDK version and which OS X version of the build system, the effects of this bug can range from a few compile warning messages (and possible subtle execution errors) to a catastrophic build failure of the _sqlite3 extension.  The attached patches fix the problem.  One consequence of fixing the bug is that it is more important than ever to supply a local newer version of libsqlite3 if building with the obsolete MacOSX10.4u.sdk since the version of libsqlite3 in 10.4 is 3.1.3 and there are several conditional tests in the _sqlite modules to work around bugs and missing features for versions that old, tests that were previously incorrectly checking the system libsqlite3 version.  (By contrast, the version of libsqlite3 in MacOSX10.5.sdk is 3.4.0, old but usable; 10.6 has 3.6.12).