gnulib: add getopt module

Unconditionally use gnulib's getopt module. This is needed by the bhyve driver
to provide a reentrant interface for getopt.

Several gnulib headers rely on features.h being included by ctype.h to provide
__GNUC_PREREQ, but on systems without glibc, this is not provided. In these
cases __GNUC_PREREQ gets redefined to 0, which causes build errors from checks
in src/internal.h.
Therefore, define __GNUC_PREREQ as early as possible. config-post.h is probably
the first header that is included, before any other headers.

bootstrap.conf

@@ -54,6 +54,7 @@ func
 getaddrinfo
 getcwd-lgpl
 gethostname
+getopt-posix
 getpass
 getpeername
 getsockname

config-post.h

@@ -69,3 +69,21 @@
 # undef WITH_SECDRIVER_APPARMOR
 # undef WITH_CAPNG
 #endif /* LIBVIRT_NSS */
+
+/*
+ * Define __GNUC__ to a sane default if it isn't yet defined.
+ * This is done here so that it's included as early as possible; gnulib relies
+ * on this to be defined in features.h, which should be included from ctype.h.
+ * This doesn't happen on many non-glibc systems.
+ * When __GNUC__ is not defined, gnulib defines it to 0, which breaks things.
+ */
+#ifdef __GNUC__
+# ifndef __GNUC_PREREQ
+#  if defined __GNUC__ && defined __GNUC_MINOR__
+#   define __GNUC_PREREQ(maj, min)                                        \
+   ((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
+#  else
+#   define __GNUC_PREREQ(maj, min) 0
+#  endif
+# endif
+#endif

m4/virt-driver-bhyve.m4

@@ -52,6 +52,9 @@ AC_DEFUN([LIBVIRT_DRIVER_CHECK_BHYVE],[
     AM_CONDITIONAL([WITH_BHYVE], [test "$with_bhyve" = "yes"])
 ])
 
+dnl Build with gnulib's getopt which contains a reentrant interface
+AC_DEFUN([gl_REPLACE_GETOPT_ALWAYS], [])
+
 AC_DEFUN([LIBVIRT_DRIVER_RESULT_BHYVE],[
     AC_MSG_NOTICE([    Bhyve: $with_bhyve])
 ])

po/POTFILES.in

@@ -8,6 +8,7 @@ daemon/remote.c
 daemon/remote_dispatch.h
 daemon/stream.c
 gnulib/lib/gai_strerror.c
+gnulib/lib/getopt.c
 gnulib/lib/regcomp.c
 src/access/viraccessdriverpolkit.c
 src/access/viraccessmanager.c