Compilation broken with STLPort

[Andrey Semashev]

Boost.ProgramOptions fails to compile on Linux with GCC 4.6 and STLPort 5.2.1 with the following error:

libs/program_options/src/options_description.cpp: In function ‘void boost::program_options::{anonymous}::format_paragraph(stlp_std::ostream&, stlp_std::string, unsigned int, unsigned int)’:
libs/program_options/src/options_description.cpp:472:70: error: no matching function for call to ‘distance(const value_type*&, const value_type* const&)’
libs/program_options/src/options_description.cpp:472:70: note: candidate is:
./boost/range/distance.hpp:27:5: note: template<class T> typename boost::range_difference::type boost::distance(const T&)
libs/program_options/src/options_description.cpp:492:84: error: no matching function for call to ‘distance(const value_type*&, const value_type*&)’
libs/program_options/src/options_description.cpp:492:84: note: candidate is:
./boost/range/distance.hpp:27:5: note: template<class T> typename boost::range_difference::type boost::distance(const T&)

The attached patch resolves the problem.

[Andrey Semashev]

The patch agains the release branch.

[Vladimir Prus]

(In [79280]) Qualify 'distance' with 'std'.

Fixes #7086.