filesystem::path::{separator,preferred_separator,dot} should have definitions

[Yegor Derevenets <yegor.derevenets@…>]

Static constexpr members of boost::filesystem::path should have definitions. Currently they do not, which leads to, e.g., the following code not compiling:

$ cat main.cpp
#include <boost/filesystem/path.hpp>

void f(const char &) {
}

int main() {
        f(boost::filesystem::path::preferred_separator);
}

$ g++ -std=c++14 -lboost_filesystem -lboost_system main.cpp
/tmp/ccuhjyO3.o: In function `main':
main.cpp:(.text+0x12): undefined reference to `boost::filesystem::path::preferred_separator'
collect2: error: ld returned 1 exit status

[Yegor Derevenets <yegor.derevenets@…>]

A possible fix: ​https://github.com/boostorg/filesystem/pull/40

[Andrey Semashev]

Fixed in ​https://github.com/boostorg/filesystem/commit/8de281773f71b04b73c048a7b48e100cbfce92b0.