nmap: use system liblinear

Use system liblinear instead of using included liblinear.
liblinear in buildroot is at version 2.20 released on December 2017
whereas liblinear in nmap has not been updated since 7 years (except for
liblinear.vcxproj which has been updated 2 years ago)

Do not use --with-liblinear option as otherwise nmap will forget to add
-llinear to LIBS due to the following line in configure.ac:

if test $have_liblinear != yes; then
  AC_CHECK_HEADERS([linear.h],
    AC_CHECK_LIB(linear, predict, [have_liblinear=yes; LIBLINEAR_LIBS="-llinear"; break],, [-lm])
)

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit c0d9ba562c5522096d4ed70827c599c9a0e9aa7c)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/nmap/Config.in

@@ -3,6 +3,7 @@ config BR2_PACKAGE_NMAP
 	depends on BR2_INSTALL_LIBSTDCPP
 	depends on BR2_USE_MMU # fork()
 	depends on BR2_TOOLCHAIN_HAS_THREADS
+	select BR2_PACKAGE_LIBLINEAR
 	select BR2_PACKAGE_LIBPCAP
 	select BR2_PACKAGE_NMAP_NMAP \
 	       if !BR2_PACKAGE_NMAP_NCAT && !BR2_PACKAGE_NMAP_NPING && !BR2_PACKAGE_NMAP_NDIFF

package/nmap/nmap.mk

@@ -7,9 +7,9 @@
 NMAP_VERSION = 7.70
 NMAP_SITE = https://nmap.org/dist
 NMAP_SOURCE = nmap-$(NMAP_VERSION).tar.bz2
-NMAP_DEPENDENCIES = libpcap
+NMAP_DEPENDENCIES = liblinear libpcap
 NMAP_CONF_OPTS = --without-liblua --without-zenmap \
-	--with-libdnet=included --with-liblinear=included
+	--with-libdnet=included
 NMAP_LICENSE = nmap license
 NMAP_LICENSE_FILES = COPYING