Trac #21706: Fix autotools/texinfo/ncurses problem, change autotools …

…package from experimental to optional

The autotools package was changed from optional to experimental in
#18563, which made this change for various packages.

The reason for changing autotools (missing xz dependency of libtool) has
since been fixed in #21047.

The branch also fixes a build problem of autotools (texinfo) involving
ncurses.

URL: https://trac.sagemath.org/21706
Reported by: mkoeppe
Ticket author(s): Matthias Koeppe
Reviewer(s): Dima Pasechnik

build/pkgs/autotools/patches/texinfo-libtinfo.patch

@@ -0,0 +1,15 @@
+* Our ncurses package is built using configure option --with-termlib, which causes tgetent and friends to be put into the separate library libtinfo, not libncurses.
+* The ancient texinfo 4.13 that is used by our autotools package (with comment "texinfo 5.x breaks building old versions of autotools...") does not know about libtinfo.
+
+diff -r -u texinfo-4.13.orig/configure texinfo-4.13/configure
+--- src.orig/texinfo-4.13/configure	2008-09-18 11:46:26.000000000 -0700
++++ src/texinfo-4.13/configure	2016-10-18 00:04:15.000000000 -0700
+@@ -17477,7 +17477,7 @@
+ # rather ncurses.  So we check for it.
+ TERMLIBS=
+ # Check for termlib before termcap because Solaris termcap needs libucb.
+-TERMLIB_VARIANTS="ncurses curses termlib termcap terminfo"
++TERMLIB_VARIANTS="ncurses tinfo curses termlib termcap terminfo"
+ for termlib in ${TERMLIB_VARIANTS}; do
+   as_ac_Lib=`$as_echo "ac_cv_lib_${termlib}''_tgetent" | $as_tr_sh`
+ { $as_echo "$as_me:$LINENO: checking for tgetent in -l${termlib}" >&5

build/pkgs/autotools/type

@@ -1 +1 @@
-experimental
+optional