ncurses: Abstract out termlib

termlib needs to be disabled on some targets e.g. mingw
this change paves the way for doing that. Functionally
it does not change anything for other platforms

(From OE-Core rev: 88f33e1e5ba4f85093f60a296cba3ee1c1341c43)

(From OE-Core rev: 82fc84b059367917690336d279cd8cab679d63ed)

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Armin Kuster <akuster808@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-core/ncurses/ncurses.inc

@@ -59,6 +59,7 @@ EX_TERMCAP_class-nativesdk = ":/etc/termcap:/usr/share/misc/termcap"
 EX_TERMINFO = ""
 EX_TERMINFO_class-native = ":/etc/terminfo:/usr/share/terminfo:/usr/share/misc/terminfo:/lib/terminfo"
 EX_TERMINFO_class-nativesdk = ":/etc/terminfo:/usr/share/terminfo:/usr/share/misc/terminfo:/lib/terminfo"
+EX_TERMLIB ?= "tinfo"
 
 # Helper function for do_configure to allow multiple configurations
 # $1 the directory to run configure in
@@ -80,7 +81,7 @@ ncurses_configure() {
 	        --disable-big-core \
 	        --program-prefix= \
 	        --with-ticlib \
-	        --with-termlib=tinfo \
+	        --with-termlib=${EX_TERMLIB} \
 	        --enable-sigwinch \
 	        --enable-pc-files \
 	        --disable-rpath-hack \