gh-38966: Clean up Cygwin remnants

We dropped support for Cygwin a while ago, but there is some stuff left
over in the tree. Let's finally remove it.

URL: #38966
Reported by: Michael Orlitzky
Reviewer(s): Kwankyu Lee

build/bin/sage-guess-package-system

@@ -32,12 +32,5 @@ elif xbps-install --version > /dev/null 2>&1; then
 elif pkg -v > /dev/null 2>&1; then
     echo freebsd
 else
-    case `uname -s` in
-        CYGWIN*)
-            echo cygwin
-            ;;
-        *)
-            echo unknown
-            ;;
-    esac
+    echo unknown
 fi

build/bin/sage-print-system-package-command

@@ -182,12 +182,6 @@ case $system:$command in
     slackware*:install)
         [ -n "$system_packages" ] && print_shell_command ${SUDO}slackpkg install $system_packages
         ;;
-    cygwin*:update)
-        print_comment "first install apt-cyg from https://github.com/transcode-open/apt-cyg"
-        ;;
-    cygwin*:install)
-        [ -n "$system_packages" ] && print_shell_command apt-cyg install $system_packages
-        ;;
     freebsd*:install)
         [ -n "$system_packages" ] && print_shell_command ${SUDO}pkg install $system_packages
         ;;

build/bin/sage-spkg-info

@@ -85,7 +85,6 @@ for system in $systems; do
             alpine)     tab "Alpine";;
             arch)       tab "Arch Linux";;
             conda)      tab "conda-forge";;
-            cygwin)     tab "Cygwin";;
             debian)     tab "Debian/Ubuntu";;
             fedora)     tab "Fedora/Redhat/CentOS";;
             freebsd)    tab "FreeBSD";;

build/pkgs/configure/checksums.ini

@@ -1,3 +1,3 @@
 tarball=configure-VERSION.tar.gz
-sha1=490f6d988c1c4c0786a0c8b36e708db56e17bfa6
-sha256=2e2b6821c9abd7d2b910edb1237f3622e985a2321cf1eedb2161b714494c6643
+sha1=b57fc7a6adb26a01f6b49cd5599221d8fb369a77
+sha256=da2ce0e892f28c583f6f43238d295375db66275d9196222e3859743260296674

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-93661cbe00c3e83691d6ed8c64586163cfdae62f
+20ad1c640949d5999c11148295ef4f856b2e745e

build/pkgs/python3/spkg-configure.m4

@@ -70,12 +70,6 @@ SAGE_SPKG_CONFIGURE([python3], [
           sage_spkg_install_python3=yes
       ])
     ])
-    AS_CASE([$host],
-            [*-*-cygwin*], [AS_VAR_IF([sage_spkg_install_python3], [yes], [
-                                AS_VAR_APPEND([SAGE_SPKG_ERRORS], ["
-  On Cygwin, python3 must be installed as a system package. This is an error."])
-                            ])
-                           ])
 ],, [
     dnl PRE
 ], [

build/pkgs/sqlite/spkg-configure.m4

@@ -33,15 +33,8 @@ SAGE_SPKG_CONFIGURE([sqlite], [
   m4_popdef([SAGE_SQLITE3_MIN_VERSION_MICRO])
   m4_popdef([SAGE_SQLITE3_MIN_VERSION])
 ], [dnl REQUIRED-CHECK
-  AS_CASE([$host],
-          [*-*-cygwin*], [
-            dnl sqlite SetDllDirectory in sage_ostools.pyx
-            sage_require_sqlite=yes
-          ], [
-            AC_REQUIRE([SAGE_SPKG_CONFIGURE_PYTHON3])
-            AS_IF([test x$sage_spkg_install_python3 = xno], [
-                sage_require_sqlite=no
-            ])
-          ])
-]
-)
+  AC_REQUIRE([SAGE_SPKG_CONFIGURE_PYTHON3])
+  AS_IF([test x$sage_spkg_install_python3 = xno], [
+    sage_require_sqlite=no
+  ])
+])

src/doc/en/developer/portability_testing.rst

@@ -259,7 +259,7 @@ This information comes from Sage's database of equivalent system
 packages.  For example::
 
   $ ls build/pkgs/flint/distros/
-  alpine.txt  cygwin.txt  fedora.txt   gentoo.txt    macports.txt  opensuse.txt  void.txt
+  alpine.txt  fedora.txt  gentoo.txt   macports.txt  opensuse.txt  void.txt
   conda.txt   debian.txt  freebsd.txt  homebrew.txt  nix.txt       repology.txt
   $ cat build/pkgs/flint/distros/debian.txt
   libflint-dev