From 52ab95873d5f2d7712edd90c9bd614f8488fd573 Mon Sep 17 00:00:00 2001
From: Fredrik Thulin <fredrik@yubico.com>
Date: Sun, 6 Mar 2011 20:19:22 +0100
Subject: [PATCH] Use AC_CHECK_LIB to check for FreeBSD libusb.

Can't use AC_LIB_HAVE_LINKFLAGS twice since the result is cached.
---
 configure.ac | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/configure.ac b/configure.ac
index f065f1b..ed5a393 100644
--- a/configure.ac
+++ b/configure.ac
@@ -83,18 +83,25 @@ if test "x$with_backend" = "xlibusb-1.0"; then
 fi
 
 if test x$with_backend = xlibusb; then
-  AC_LIB_HAVE_LINKFLAGS(usb,, [#include <libusb.h>], [libusb_init(NULL)])
-  if test "$ac_cv_libusb" = yes; then
-    # FreeBSD 8 has an implementation of the libusb-1.0 API in -lusb
+  freebsd_libusb_found=no
+  AC_CHECK_LIB(usb, libusb_init, [freebsd_libusb_found=yes])
+  if test "$freebsd_libusb_found" = yes; then
+    # FreeBSD 8 has an implementation of the libusb-1.0 API in -lusb,
+    # interestingly enough together with most of libusb-0 API, so this
+    # check has to be before the generic libusb-0 check
+    AC_LIB_HAVE_LINKFLAGS(usb,, [#include <libusb.h>], [libusb_init(NULL)])
     with_backend=libusb-1.0
-  else
+  fi
+
+  if test "$ac_cv_libusb" != yes; then
     AC_LIB_HAVE_LINKFLAGS(usb,, [#include <usb.h>], [usb_init()])
-    if test "$ac_cv_libusb" != yes; then
-      if test "$with_backend_orig" = "check"; then
-       AC_MSG_ERROR([libusb-1.0 or libusb not found, please install one of them])
-      else
-        AC_MSG_ERROR([libusb not found, please install usb.h and libusb.so])
-      fi
+  fi
+
+  if test "$ac_cv_libusb" != yes; then
+    if test "$with_backend_orig" = "check"; then
+      AC_MSG_ERROR([libusb-1.0 or libusb not found, please install one of them])
+    else
+      AC_MSG_ERROR([libusb not found, please install usb.h and libusb.so])
     fi
   fi
 fi
-- 
2.39.5