This avoids the building of lirc_gpio and lirc_parallel.

Since SMP-Kernels are usual today, lirc_parallel would break the build.

see lirc_parallel.c:
#ifdef CONFIG_SMP
#error "--- Sorry, this driver is not SMP safe. ---"
#endif

lirc_gpio uses 2 functions, not exported by the kernel shipped with Slackware 12.2.
These were: bttv_get_cardinfo and bttv_get_gpio_queue

diff -uprN lirc-0.8.4a_orig/configure lirc-0.8.4a/configure
--- lirc-0.8.4a_orig/configure	2008-10-26 15:13:42.000000000 +0100
+++ lirc-0.8.4a/configure	2009-01-07 07:04:05.805431467 +0100
@@ -25861,7 +25861,6 @@ elif test "$lirc_driver" = "all"; then
 	lirc_atiusb \
 	lirc_bt829 \
 	lirc_cmdir \
-	lirc_gpio \
 	lirc_i2c \
 	lirc_igorplugusb \
 	lirc_imon \
@@ -25869,7 +25868,6 @@ elif test "$lirc_driver" = "all"; then
 	lirc_ite8709 \
 	lirc_mceusb \
 	lirc_mceusb2 \
-	lirc_parallel \
 	lirc_sasem \
 	lirc_serial \
 	lirc_sir \