due to l2tp doesn't require libnl more build it by default

README

@@ -41,9 +41,9 @@ or specify other location via KDIR.
 1. cd /path/to/accel-pptp-1.1
 2. mkdir build
 3. cd build
-4. cmake [-DBUILD_DRIVER=TRUE] [-DKDIR=/usr/src/linux] [-DCMAKE_INSTALL_PREFIX=/usr/local] [-DCMAKE_BUILD_TYPE=Debug] [-DLOG_PGSQL=TRUE] [-DL2TP=TRUE] [-DSHAPER=TRUE] ..
+4. cmake [-DBUILD_DRIVER=TRUE] [-DKDIR=/usr/src/linux] [-DCMAKE_INSTALL_PREFIX=/usr/local] [-DCMAKE_BUILD_TYPE=Debug] [-DLOG_PGSQL=TRUE] [-DSHAPER=TRUE] ..
    Please note that the double dot record in the end of the command is essential. You'll get error if you miss it.
-   BUILD_DRIVER, KDIR, CMAKE_INSTALL_PREFIX, CMAKE_BUILD_TYPE, LOG_PGSQL, L2TP, SHAPER  are optional,
+   BUILD_DRIVER, KDIR, CMAKE_INSTALL_PREFIX, CMAKE_BUILD_TYPE, LOG_PGSQL, SHAPER  are optional,
    but while pptp is not present in mainline kernel you probably need BUILD_DRIVER.
 5. make
 6. make install

accel-pptpd/ctrl/CMakeLists.txt

 ADD_SUBDIRECTORY(pptp)
 ADD_SUBDIRECTORY(pppoe)
-
-IF (L2TP)
-	ADD_SUBDIRECTORY(l2tp)
-ENDIF (L2TP)
-
+ADD_SUBDIRECTORY(l2tp)

contrib/gentoo/net-dialup/accel-pptp/accel-pptp-9999.ebuild

@@ -14,12 +14,11 @@ HOMEPAGE="http://accel-pptp.sourceforge.net/"
 SLOT="0"
 LICENSE="GPL"
 KEYWORDS="~amd64 ~x86"
-IUSE="postgres debug l2tp shaper"
+IUSE="postgres debug shaper"
 
 DEPEND=">=sys-libs/glibc-2.8
 	dev-libs/openssl
 	dev-libs/libaio
-	l2tp? ( =dev-libs/libnl-9999 )
 	shaper? ( =dev-libs/libnl-9999 )
 	postgres? ( >=dev-db/postgresql-base-8.1 )"
 
@@ -51,10 +50,6 @@ src_configure() {
 		mycmakeargs+=( "-DLOG_PGSQL=TRUE" )
 	fi
 	
-	if use l2tp; then
-		mycmakeargs+=( "-DL2TP=TRUE" )
-	fi
-
 	if use shaper; then
 		mycmakeargs+=( "-DSHAPER=TRUE" )
 	fi