When I want to build misc/kdepim3 on Slackware Linux using the current
pkgsrc branch, I get:

configure: error: You need to have flex installed.
*** Error code 1

These are the relevant lines of config.log:

configure:33681: checking for flex
configure:33697: found /usr/pkg/bin/flex
configure:33707: result: flex
configure:33720: checking for yywrap in -lfl
configure:33750: gcc -o conftest -std=iso9899:1990 -W -Wall
-Wchar-subscripts -Wshadow -Wpointer-arith -Wmissing-prototypes
-Wwrite-strings -D_XOPEN_SOURCE=500 -D_BSD_SOURCE -DNDEBUG -O2  -O2
-march=athlon-xp -I/usr/pkg/include -I/usr/include -DLDAP_DEPRECATED
-I/usr/pkg/qt3/include -DGLX_GLXEXT_LEGACY -I/usr/pkg/include/krb5
-I/usr/pkg/include/db4 -I/usr/pkg/include/freetype2 -Wformat-security
-Wmissing-format-attribute  -DQT_THREAD_SUPPORT -I/usr/pkg/include
-I/usr/include -DLDAP_DEPRECATED -I/usr/pkg/qt3/include
-DGLX_GLXEXT_LEGACY -I/usr/pkg/include/krb5 -I/usr/pkg/include/db4
-I/usr/pkg/include/freetype2 -D_REENTRANT -L/usr/pkg/qt3/lib
-L/usr/pkg/xorg/lib -Wl,-R/usr/pkg/xorg/lib -L/usr/pkg/lib
-Wl,-R/usr/pkg/lib -L/usr/lib -Wl,-R/usr/lib -lrfuncs
-Wl,-R/usr/pkg/qt3/lib conftest.c -lfl  -ldb4 >&5
/usr/lib/gcc/i486-slackware-linux/3.4.6/../../../../i486-slackware-linux/bin/ld:
cannot find -lfl
collect2: ld returned 1 exit status