libisds licence correction

libisds license was corrected from "LGPLv3" to "LGPLv3+ and GPLv3+".

I discovered during a rebase to 0.11 version that bundled gettext.h
header file is GPLv3+ licensed while all the other code is LGPLv3+.
Although one can argue that the few gettext.h macros are not
a substantial work, it's still a GPL code that imposes GPL conditions on
the resulting library.

I raised the issue to gettext upstream
<> as I believe any non-GPLv3
softare that follows the gettext guidelines (include gettext.h) is

-- Petr