Execution of boost_mpl_preprocess.py fails if $(boost_root) path contains the string "linux"

[Mihai Pop <mihaipop11@…>]

How to reproduce:

Build System: Ubuntu 16.04.0 LTS GCC: all

Let's say that we have the boost sources in /tmp/boost-linux/boost_1_X_X

The important thing is to have the string linux in the boost-root variable.

Error log:

python boost_mpl_preprocess.py             
In file included from /tmp/boost-linux/boost_1_63_0/libs/mpl/preprocessed/vector/vector40.cpp:15:0:
/tmp/boost-linux/boost_1_63_0/boost/config.hpp:30:29: fatal error: /tmp/boost-1/boost_1_63_0/libs/mpl/preprocessed/include/plain/user.hpp: No such file or directory
compilation terminated.
In file included from /tmp/boost-linux/boost_1_63_0/libs/mpl/preprocessed/vector/vector70.cpp:15:0:
/tmp/boost-linux/boost_1_63_0/boost/config.hpp:30:29: fatal error: /tmp/boost-1/boost_1_63_0/libs/mpl/preprocessed/include/plain/user.hpp: No such file or directory
compilation terminated.
In file included from /tmp/boost-linux/boost_1_63_0/libs/mpl/preprocessed/vector/vector30.cpp:15:0:
/tmp/boost-linux/boost_1_63_0/boost/config.hpp:30:29: fatal error: /tmp/boost-1/boost_1_63_0/libs/mpl/preprocessed/include/plain/user.hpp: No such file or directory
compilation terminated.

Problem: This appears because in preprocess.cmd gcc is invoked with include files included with angle brackets, so if we have the string linux it will be evaluated to 1 because it is a macro

[Mihai Pop <mihaipop11@…>]

linux is a macro defined to 1. In <> case the macro is expanded while in "" case, the token is a string.