backports / lzma / _lzmamodule.c (115): schwerwiegender Fehler C1083: Include-Datei kann nicht geöffnet werden: 'lzma.h': Keine solche Datei oder Verzeichnis

Ich habe einen Windows 7-PC, auf dem Visual Studio 2015 Upgrade 3 installiert ist, und ich möchte die Bibliothek backports.lzma für Python mit pip installieren.

Ich habe XZ Utils im Ordner Programme heruntergeladen und entpackt. (XZ Utils ist für die Installation der Backports-Bibliothek obligatorisch, wie von der Pypi-Site angegeben. )

Dies ist die Pip-Ausgabe:

Installing collected packages: backports.lzma Running setup.py install for backports.lzma: started Running setup.py install for backports.lzma: finished with status 'error' Complete output from command "C:\Program Files (x86)\Python27\python.exe" -u -c "import setuptools, tokenize;__file__='c:\\users\\myuser\\appdata\\local\\temp\\pip-build-smbn4k\\backports.lzma\\setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record c:\users\myuser\appdata\local\temp\pip-hfgg8w-record\install-record.txt --single-version-externally-managed --compile: This is backports.lzma version 0.0.8 running install running build running build_py creating build creating build\lib.win32-2.7 creating build\lib.win32-2.7\backports copying backports\__init__.py -> build\lib.win32-2.7\backports creating build\lib.win32-2.7\backports\lzma copying backports\lzma\__init__.py -> build\lib.win32-2.7\backports\lzma running build_ext building 'backports/lzma/_lzma' extension creating build\temp.win32-2.7 creating build\temp.win32-2.7\Release creating build\temp.win32-2.7\Release\backports creating build\temp.win32-2.7\Release\backports\lzma C:\Users\myuser\AppData\Local\Programs\Common\Microsoft\Visual C++ for Python\9.0\VC\Bin\cl.exe /c /nologo /Ox /MD /W3 /GS- /DNDEBUG "-IC:\Program Files (x86)\Python27\include" -IC:\Users\myuser\include -I/opt/local/include -I/usr/local/include "-IC:\Program Files (x86)\Python27\include" "-IC:\Program Files (x86)\Python27\PC" /Tcbackports/lzma/_lzmamodule.c /Fobuild\temp.win32-2.7\Release\backports/lzma/_lzmamodule.obj _lzmamodule.c backports/lzma/_lzmamodule.c(32) : warning C4273: 'PyErr_NewExceptionWithDoc' : inconsistent dll linkage C:\Program Files (x86)\Python27\include\pyerrors.h(226) : see previous definition of 'PyErr_NewExceptionWithDoc' backports/lzma/_lzmamodule.c(115) : fatal error C1083: Cannot open include file: 'lzma.h': No such file or directory error: command 'C:\\Users\\myuser\\AppData\\Local\\Programs\\Common\\Microsoft\\Visual C++ for Python\\9.0\\VC\\Bin\\cl.exe' failed with exit status 2  ---------------------------------------- Failed building wheel for backports.lzma Command ""C:\Program Files (x86)\Python27\python.exe" -u -c "import setuptools, tokenize;__file__='c:\\users\\myuser\\appdata\\local\\temp\\pip-build-smbn4k\\backports.lzma\\setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record c:\users\myuser\appdata\local\temp\pip-hfgg8w-record\install-record.txt --single-version-externally-managed --compile" failed with error code 1 in c:\users\myuser\appdata\local\temp\pip-build-smbn4k\backports.lzma\ 'backports.lzma' failed to install. Exit code: 1 

In Program Files \ xz \ include befindet sich die Datei lzma.h. Wie verlinke ich den Header, um erkannt zu werden?