Trac #25680: Upgrade to Python 3.7.x

'''Tarball''':
https://www.python.org/ftp/python/3.7.3/Python-3.7.3.tar.xz

URL: https://trac.sagemath.org/25680
Reported by: jdemeyer
Ticket author(s): Jeroen Demeyer
Reviewer(s): Vincent Klein, Erik Bray, Frédéric Chapoton

Author: Release Manager

build/pkgs/python3/checksums.ini

@@ -1,4 +1,4 @@
-tarball=Python-VERSION.tar.gz
-sha1=ae1fc9ddd29ad8c1d5f7b0d799ff0787efeb9652
-md5=9a080a86e1a8d85e45eee4b1cd0a18a2
-cksum=3720721727
+tarball=Python-VERSION.tar.xz
+sha1=e3584650a06ae2765da0678176deae9d133f1b3d
+md5=93df27aec0cd18d6d42173e601ffbbfd
+cksum=1160005949

build/pkgs/python3/dependencies

@@ -1,4 +1,4 @@
-zlib readline sqlite libpng bzip2 xz
+zlib readline sqlite libpng bzip2 xz libffi
 
 ----------
 All lines of this file are ignored except the first.

build/pkgs/python3/package-version.txt

@@ -1 +1 @@
-3.6.6.p0
+3.7.3.p0

build/pkgs/python3/patches/2.6.5-ncurses-abi6.patch

@@ -1,10 +1,9 @@
-diff --git a/Lib/distutils/unixccompiler.py b/Lib/distutils/unixccompiler.py
-index 3f321c2..cc295a3 100644
---- a/Lib/distutils/unixccompiler.py
-+++ b/Lib/distutils/unixccompiler.py
-@@ -236,7 +236,7 @@ class UnixCCompiler(CCompiler):
-         elif sys.platform[:7] == "irix646" or sys.platform[:6] == "osf1V5":
-             return ["-rpath", dir]
+diff -ru a/Lib/distutils/unixccompiler.py b/Lib/distutils/unixccompiler.py
+--- a/Lib/distutils/unixccompiler.py	2018-06-27 05:07:35.000000000 +0200
++++ b/Lib/distutils/unixccompiler.py	2018-06-28 09:32:52.719006731 +0200
+@@ -234,7 +234,7 @@
+                 return ["-Wl,+s", "-L" + dir]
+             return ["+s", "-L" + dir]
          else:
 -            if self._is_gcc(compiler):
 +            if sys.platform[:5] == "linux" or self._is_gcc(compiler):