isatty: Make it return true in Cygwin consoles on native Windows. * lib/isatty.c: Include <string.h>. (GetProcAddress): New macro. (GetNamedPipeClientProcessIdFuncType): New type. (GetNamedPipeClientProcessIdFunc): New variable. (QueryFullProcessImageNameFuncType): New type. (QueryFullProcessImageNameFunc): New variable. (initialized): New variable. (initialize): New function. (IsCygwinConsoleHandle): New function. (isatty): Invoke it. * doc/posix-functions/isatty.texi: Mention the issue.

#!/bin/sh

# Test in an ISO-8859-1 or ISO-8859-15 locale.
: ${LOCALE_FR=fr_FR}
if test $LOCALE_FR = none; then
  if test -f /usr/bin/localedef; then
    echo "Skipping test: no traditional french locale is installed"
  else
    echo "Skipping test: no traditional french locale is supported"
  fi
  exit 77
fi

LC_ALL=$LOCALE_FR \
${CHECKER} ./test-c-vsnprintf${EXEEXT} 1