Bump buidlroot version to 2018.02.6

bsp/buildroot/package/exim/0001-Build-buildconfig-for-the-host.patch

@@ -17,7 +17,7 @@ index 29a6ad3..420ba60 100644
 -	@echo "$(CC) buildconfig.c"
 -	$(FE)$(CC) $(CFLAGS) $(INCLUDE) -o buildconfig buildconfig.c $(LIBS)
 +	@echo "$(HOSTCC) buildconfig.c"
-+	$(FE)$(HOSTCC) $(HOSTCFLAGS) $(INCLUDE) -o buildconfig buildconfig.c $(LIBS)
++	$(FE)$(HOSTCC) $(HOSTCFLAGS) $(INCLUDE) -o buildconfig buildconfig.c
  
  
  # Target for the exicyclog utility script

bsp/buildroot/package/exim/Config.in

@@ -8,8 +8,9 @@ config BR2_PACKAGE_EXIM
 	select BR2_PACKAGE_PCRE
 	select BR2_PACKAGE_BERKELEYDB
 	help
-	  Exim is a message transfer agent (MTA) developed at the University of
-	  Cambridge for use on Unix systems connected to the Internet.
+	  Exim is a message transfer agent (MTA) developed at the
+	  University of Cambridge for use on Unix systems connected to
+	  the Internet.
 
 	  http://www.exim.org/
 

bsp/buildroot/package/exim/exim.mk

@@ -7,7 +7,7 @@
 EXIM_VERSION = 4.89.1
 EXIM_SOURCE = exim-$(EXIM_VERSION).tar.xz
 EXIM_SITE = ftp://ftp.exim.org/pub/exim/exim4
-EXIM_LICENSE = GPLv2+
+EXIM_LICENSE = GPL-2.0+
 EXIM_LICENSE_FILES = LICENCE
 EXIM_DEPENDENCIES = pcre berkeleydb host-pkgconf