mir examples/progressbar.c uses internal C define (can't build on other distros)

[Allison Karlitskaya]

This example program does #define __USE_BSD 1 but the __USE_BSD macro is an internal private define for use by the C library itself. This causes problems with newer versions of glibc.

The correct solution here is to use _BSD_SOURCE but apparently this is deprecated in newer versions of glibc for favour of _DEFAULT_SOURCE.

In order to work with both old and new we should define both as explained here:

/* _BSD_SOURCE and _SVID_SOURCE are deprecated aliases for
   _DEFAULT_SOURCE. If _DEFAULT_SOURCE is present we do not
   issue a warning; the expectation is that the source is being
   transitioned to use the new macro. */
#if (defined _BSD_SOURCE || defined _SVID_SOURCE) \
    && !defined _DEFAULT_SOURCE
# warning "_BSD_SOURCE and _SVID_SOURCE are deprecated, use _DEFAULT_SOURCE"
# undef _DEFAULT_SOURCE
# define _DEFAULT_SOURCE 1
#endif

[Allison Karlitskaya (desrt)]

fwiw this is fairly low priority for me -- both this and the gflags bugs are now being vendor-patched by jhbuild for now.

[PS Jenkins bot (ps-jenkins)]

Fix committed into lp:mir at revision None, scheduled for release in mir, milestone 0.9.0