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From: "Andris Pavenis (andris DOT pavenis AT iki DOT fi) [via djgpp AT delorie DOT com]" <djgpp AT delorie DOT com>
Subject: gcc-7 and std::experimental::filesystem
To: "DJGPP List (E-mail)" <djgpp AT delorie DOT com>
Message-ID: <2ec3037c-668f-c5b8-b4cb-55945d0038b2@iki.fi>
Date: Sun, 28 May 2017 18:13:49 +0300
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Noticed that std::experimental::filesystem support is not compiled in for DJGPP.

Default value in configuration parameter --enable-libstdcxx-filesystem-ts is auto which only 
enables support for predefined targets. DJGPP is not between them.

Attempted to enable it (for building cross-compiler):

1) S_ISSOCK used in one place (can easily be ifdefed out)

2) 2 error constants std::errc::not_supported and std::errc::operation_not_supported used which are 
not defined for DJGPP. Corersponding errno macros are ENOTSUP and EOPNOSUPP. Second macro is 
present in wat3222br6.zip, but none of them in djdev205.zip. Presence of the first is checked by 
configure script (_GLIBCXX_HAVE_ENOTSUP).

Adding these 2 macros would allow filesystem library (libstdc++fs.a) to be built, but we would need 
to think how to rename it to avoid SFN conflict with libstdc++.a (after replacing ++ with xx).  I 
have however not tested if it is so. Also that would require making release of DJGPP v2.06 with 
some changes.

Andris