stdio: Fix compilation error on DragonFly BSD

[Bruno Haible]

Building a testdir on DragonFly BSD 6.0, I see this error:

In file included from ../../gltests/test-stdio-c++.cc:22:
../gllib/stdio.h: In member function 'gnulib::_gl_fcloseall_wrapper::operator 
gnulib::_gl_fcloseall_wrapper::type() const':
../gllib/stdio.h:755:1: error: invalid conversion from 'void (*)()' to 
'gnulib::_gl_fcloseall_wrapper::type' {aka 'int (*)()'} [-fpermissive]
 _GL_CXXALIAS_SYS (fcloseall, int, (void));
 ^~~~~~~~~~~~~~~~

This patch fixes it.


2021-05-22  Bruno Haible  <br...@clisp.org>

        stdio: Fix compilation error on DragonFly BSD.
        * lib/stdio.in.h (fcloseall): Treat DragonFly BSD like FreeBSD.

diff --git a/lib/stdio.in.h b/lib/stdio.in.h
index bbe7084..4dfa339 100644
--- a/lib/stdio.in.h
+++ b/lib/stdio.in.h
@@ -242,7 +242,7 @@ _GL_WARN_ON_USE (fclose, "fclose is not always POSIX 
compliant - "
 _GL_CXXALIAS_MDA (fcloseall, int, (void));
 # else
 #  if @HAVE_DECL_FCLOSEALL@
-#   if defined __FreeBSD__
+#   if defined __FreeBSD__ || defined __DragonFly__
 _GL_CXXALIAS_SYS (fcloseall, void, (void));
 #   else
 _GL_CXXALIAS_SYS (fcloseall, int, (void));