[perl #126306] openbsd t/io/errno.t tests fail randoml

# New Ticket Created by  Jarkko Hietaniemi 
# Please include the string:  [perl #126306]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=126306 >


(as of blead 26773d9d, but this has been there for a while, never got around to reporting...)

A random selection of the io/errno.t subtests fail, sometimes it's none, sometimes a couple.

But the error is always the same, an extra "Resource temporarily unavailable".

Curiously I have ran into a very (similar error in IRIX: https://rt.perl.org/Ticket/Display.html?id=123977 (though IIRC there all the subtests always failed reliably, and the "stale" error different... that one is still unresolved, I guess I'm one of the few people still with access to IRIX...)

j...@openbsd$ cd t
j...@openbsd$ ../perl -I../lib io/errno.t
# Failed test 9 - Wrong errno, PERLIO=stdio stdin='test\n',  at io/errno.t line 38
#      got "test\nResource temporarily unavailable"
# expected "test\n"
# Failed test 15 - Wrong errno, PERLIO=stdio stdin='test', $/=\2 at io/errno.t line 38
#      got "testResource temporarily unavailable"
# expected "test"

j...@openbsd$ ../perl -I../lib io/errno.t  2>&1 > log
# Failed test 11 - Wrong errno, PERLIO=stdio stdin='test\n', $/=\2 at io/errno.t line 38
#      got "test\nResource temporarily unavailable"
# expected "test\n"
# Failed test 16 - Wrong errno, PERLIO=stdio stdin='test', $/=\1024 at io/errno.t line 38
#      got "testResource temporarily unavailable"
# expected "test"

./perl -Ilib -V
Summary of my perl5 (revision 5 version 23 subversion 4) configuration:
   
  Platform:
    osname=openbsd, osvers=4.9, archname=OpenBSD.i386-openbsd
    uname='openbsd ... 4.9 generic#671 i386 '
    config_args='-des -Dusedevel'
    hint=recommended, useposix=true, d_sigaction=define
    useithreads=undef, usemultiplicity=undef
    use64bitint=undef, use64bitall=undef, uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_FORTIFY_SOURCE=2',
    optimize='-O2',
    cppflags='-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include'
    ccversion='', gccversion='4.2.1 20070719 ', gccosandvers='openbsd4.9'
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234, doublekind=3
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12, longdblkind=3
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags ='-Wl,-E  -fstack-protector -L/usr/local/lib'
    libpth=/usr//lib /usr/local/lib /usr/lib
    libs=-lpthread -lm -lutil -lc
    perllibs=-lpthread -lm -lutil -lc
    libc=/usr//lib/libc.so.58.0, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version=''
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags=' '
    cccdlflags='-DPIC -fPIC ', lddlflags='-shared -fPIC  -L/usr/local/lib -fstack-protector'


Characteristics of this binary (from libperl): 
  Compile-time options: HAS_TIMES PERLIO_LAYERS PERL_COPY_ON_WRITE
                        PERL_DONT_CREATE_GVSV
                        PERL_HASH_FUNC_ONE_AT_A_TIME_HARD PERL_MALLOC_WRAP
                        PERL_PRESERVE_IVUV PERL_USE_DEVEL USE_LARGE_FILES
                        USE_LOCALE USE_LOCALE_COLLATE USE_LOCALE_CTYPE
                        USE_LOCALE_NUMERIC USE_LOCALE_TIME USE_PERLIO
                        USE_PERL_ATOF
  Built under openbsd
  Compiled at Oct  9 2015 01:32:25
  @INC:
    lib
    /usr/local/lib/perl5/site_perl/5.23.4/OpenBSD.i386-openbsd
    /usr/local/lib/perl5/site_perl/5.23.4
    /usr/local/lib/perl5/5.23.4/OpenBSD.i386-openbsd
    /usr/local/lib/perl5/5.23.4
    .
j...@openbsd$