[Python-Dev] Problem building Python 2.7.5 with separate sysroot

[Paul Smith]

Hi all.  I'm trying to build Python 2.7.5 on a GNU/Linux (Linux Mint 14)
system, but using a different sysroot (that is, a separate
<d>/usr/include, <d>/usr/lib, etc., not the real one for my system).

I have shell script wrappers around GCC and its various tools that
invoke it with the right paths to force this to happen, and when I call
Python's configure I send along "CC=sysroot-gcc", etc. for all the
various tools.  Note that it's not really a cross-compilation because
the target is also a GNU/Linux system on the same hardware architecture.

The majority of Python builds just fine like this.

However, I'm having serious problems building modules such as fcntl,
etc.  Looking at the output from the makefile, I can see that somehow,
someone is forcibly adding "-I/usr/include/x86_64-linux-gnu" to the link
line:

building 'termios' extension
sysroot-gcc -pthread -fPIC -fno-strict-aliasing -g -O2 -DNDEBUG -g
-fwrapv -O3 -Wall -Wstrict-prototypes -I. -IInclude
-I/usr/include/x86_64-linux-gnu -I/common/sysroot/tools/usr/include
-I/common/sysroot/tools/usr/include-fixed -I/usr/local/include
-I/home/workspaces/psmith/python/obj/src/Python-2.7.5/Include
-I/home/workspaces/psmith/python/obj/bld/python
-c /home/workspaces/psmith/python/obj/src/Python-2.7.5/Modules/termios.c
-o
build/temp.linux-x86_64-2.7/home/workspaces/psmith/python/obj/src/Python-2.7.5/Modules/termios.o

This fails miserably because the headers
in /usr/include/x86_64-linux-gnu do not play at all nicely with my other
sysroot headers.  Ditto for other extensions like fcntl, etc.

I've searched high and low in the Python source, generated makefiles,
config.log, etc. and I cannot find where this -I flag is coming from
anywhere.  I found the --oldincludedir flag to configure and set it to
point into my sysroot as well, but that didn't help: the /usr/include
still appears when building these extensions.

Can anyone tell me where Python is getting these -I flags and what I
need to do to tell it to NOT use those flags when building extensions?

I'd also like to remove the -I/usr/local/include, although this is not
actually causing me problems right now.