Version 9.0 (bz 1756780, 1770880).

Also:
- Drop upstreamed -ecm and -primecount patches.
- Add -escape patch.
- The old notebook (sagenb) is no longer shipped, so drop the -sagenb
  and -sagenb-python3 patches, the -notebook subpackage, and some BRs.
- New -jupyter subpackage.
- Add suitesparse BR.
- Drop pathlib2 BR (bz 1797116).

sagemath-scripts.patch

@@ -1,6 +1,6 @@
 diff -up src/bin/sage.orig src/bin/sage
---- src/bin/sage.orig	2019-10-03 14:38:40.429507574 -0300
-+++ src/bin/sage	2019-10-03 14:47:00.852631198 -0300
+--- src/bin/sage.orig	2020-01-01 04:03:10.000000000 -0700
++++ src/bin/sage	2020-02-25 13:37:42.510072662 -0700
 @@ -26,13 +26,10 @@ usage() {
      echo "  file.[sage|py|spyx] -- run given .sage, .py or .spyx file"
      echo "  -advanced           -- list all command line options"
@@ -585,7 +585,7 @@ diff -up src/bin/sage.orig src/bin/sage
 -    # tends to ask interactive questions if something goes wrong. These
 -    # cause the build to hang. If stdin is /dev/null, TeX just aborts.
 -    shift
--    exec sage-python23 -m sage_setup.docbuild "$@" </dev/null
+-    exec sage-python -m sage_setup.docbuild "$@" </dev/null
 -fi
 -
  if [ "$1" = '-gdb' -o "$1" = "--gdb" ]; then
@@ -605,8 +605,8 @@ diff -up src/bin/sage.orig src/bin/sage
      exec sage-startuptime.py "$@"
  fi
 diff -up src/bin/sage-valgrind.orig src/bin/sage-valgrind
---- src/bin/sage-valgrind.orig	2019-10-03 14:47:13.247708565 -0300
-+++ src/bin/sage-valgrind	2019-10-03 14:47:46.404915531 -0300
+--- src/bin/sage-valgrind.orig	2020-01-01 04:03:10.000000000 -0700
++++ src/bin/sage-valgrind	2020-02-25 13:36:02.973848216 -0700
 @@ -4,17 +4,7 @@ if [ -z $SAGE_EXTCODE ]; then
      SAGE_EXTCODE=`${0/-valgrind} -c "from sage.env import SAGE_EXTCODE; print(SAGE_EXTCODE)"`
  fi