configure.ac: Improve a libusb-1.0 related check.

Don't rely on the "heuristic" that 'libusb_CFLAGS' will be non-empty if
libusb-1.0 was found, but rather use the proper method of checking the
variable 'have_libusb1_0' which pkg-config will set to "yes"/"no"
depending on whether it finds the library.

diff --git a/configure.ac b/configure.ac
index 8e48861be2dcddf0148dd5ac6138dd6bd608b1b5..9e52c712c203d2ad1a46394699ea2c3a415dce2a 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -228,7 +228,7 @@ case "$build" in
                LA_ZEROPLUS_LOGIC_CUBE="no"])
 
        # Define HAVE_LIBUSB_1_0 in config.h if we found libusb-1.0.
-       if test "x$libusb_CFLAGS" != "x"; then
+       if test "x$have_libusb1_0" != "xno"; then
                AC_DEFINE_UNQUOTED(HAVE_LIBUSB_1_0, [1],
                        [Specifies whether we have a libusb.h header.])
        fi