unable to install build-essential in 6.9.1

Hi,

With the new sources the problem stays the same.

# pip install sabyenc --upgrade
Downloading/unpacking sabyenc from https://pypi.python.org/packages/02/87/fedf093dbd2c426b0ead256a531d511d4800bb30163f6d5949b6f467caae/sabyenc-3.3.2.tar.gz#md5=0358d66f3bb1a79b04205088ab5a510a
  Downloading sabyenc-3.3.2.tar.gz
  Running setup.py (path:/tmp/pip-build-pYKVtF/sabyenc/setup.py) egg_info for package sabyenc
    
Installing collected packages: sabyenc
  Found existing installation: sabyenc 3.0.2
    Uninstalling sabyenc:
      Successfully uninstalled sabyenc
  Running setup.py install for sabyenc
    building 'sabyenc' extension
    arm-linux-gnueabi-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c src/sabyenc.c -o build/temp.linux-armv7l-2.7/src/sabyenc.o
    In file included from src/sabyenc.c:22:0:
    src/sabyenc.h:22:20: fatal error: Python.h: No such file or directory
     #include <Python.h>
                        ^
    compilation terminated.
    error: command 'arm-linux-gnueabi-gcc' failed with exit status 1
    Complete output from command /usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-pYKVtF/sabyenc/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-sXWG_E-record/install-record.txt --single-version-externally-managed --compile:
    running install

running build

running build_ext

building 'sabyenc' extension

creating build

creating build/temp.linux-armv7l-2.7

creating build/temp.linux-armv7l-2.7/src

arm-linux-gnueabi-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c src/sabyenc.c -o build/temp.linux-armv7l-2.7/src/sabyenc.o

In file included from src/sabyenc.c:22:0:

src/sabyenc.h:22:20: fatal error: Python.h: No such file or directory

 #include <Python.h>

                    ^

compilation terminated.

error: command 'arm-linux-gnueabi-gcc' failed with exit status 1

----------------------------------------
  Rolling back uninstall of sabyenc
Cleaning up...
Command /usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip-build-pYKVtF/sabyenc/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-sXWG_E-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /tmp/pip-build-pYKVtF/sabyenc
Storing debug log for failure in /root/.pip/pip.log

# apt-get install build-essential
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 build-essential : Depends: libc6-dev but it is not going to be installed or
                            libc-dev
                   Depends: g++ (>= 4:4.9.1) but it is not going to be installed
N: Ignoring file 'crosstools.list.no' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension
E: Unable to correct problems, you have held broken packages.

# apt-get install libc6-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 libc6-dev : Depends: libc6 (= 2.19-18+deb8u10)
N: Ignoring file 'crosstools.list.no' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension
E: Unable to correct problems, you have held broken packages.

# apt-get install libc6
Reading package lists... Done
Building dependency tree       
Reading state information... Done
libc6 is already the newest version (2.19-18+deb8u10.netgear1).
0 upgraded, 0 newly installed, 0 to remove and 69 not upgraded.
N: Ignoring file 'crosstools.list.no' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension