DEPRECATE: the original legacy mingw version 1

Remove completely in September 2023

Closes #10667

.azure-pipelines.yml

@@ -223,7 +223,7 @@ stages:
           name: 32-bit (legacy)
           container_img: ghcr.io/mback2k/curl-docker-winbuildenv/msys1-mingw:ltsc2019
           container_cmd: C:\MinGW\msys\1.0\bin\sh
-          configure: --host=i686-pc-mingw32 --build=i686-pc-mingw32 --prefix=/mingw --enable-debug --without-ssl
+          configure: --host=i686-pc-mingw32 --build=i686-pc-mingw32 --prefix=/mingw --enable-debug --without-ssl --with-mingw1-deprecated
           tests: "!203 !1143"
         v1_mingw32:
           name: 32-bit w/o zlib
@@ -255,7 +255,7 @@ stages:
           name: 32-bit Schannel/SSPI/WinIDN (legacy)
           container_img: ghcr.io/mback2k/curl-docker-winbuildenv/msys1-mingw:ltsc2019
           container_cmd: C:\MinGW\msys\1.0\bin\sh
-          configure: --host=i686-pc-mingw32 --build=i686-pc-mingw32 --prefix=/mingw --enable-debug --enable-sspi --with-schannel --with-winidn
+          configure: --host=i686-pc-mingw32 --build=i686-pc-mingw32 --prefix=/mingw --enable-debug --enable-sspi --with-schannel --with-winidn --with-mingw1-deprecated
           tests: "!203 !305 !311 !312 !313 !404 !1143 !2033 !2035 !2038 !2041 !2042 !2048 !2070 !2079 !2087 !3023 !3024"
         v1_mingw32_schannel:
           name: 32-bit Schannel/SSPI/WinIDN w/o zlib

configure.ac

@@ -612,6 +612,7 @@ case $host in
       ]])
     ],[
       curl_mingw_original=yes
+      curl_mingw_die=yes
       AC_MSG_RESULT([yes])
     ],[
       AC_MSG_RESULT([no])
@@ -619,6 +620,18 @@ case $host in
     ;;
 esac
 
+
+AC_ARG_WITH(mingw1-deprecated,dnl
+AS_HELP_STRING([--with-mingw1-deprecated],[confirm you realize support for mingw v1 is dying]),
+  if test X"$withval" != Xno; then
+    curl_mingw_die=
+  fi
+)
+
+if test -n "$curl_mingw_die"; then
+  AC_MSG_ERROR([support for mingw v1 is going away, enable temporarily with --with-mingw1-deprecated])
+fi
+
 dnl **********************************************************************
 dnl Compilation based checks should not be done before this point.
 dnl **********************************************************************

docs/DEPRECATE.md

@@ -31,6 +31,18 @@ We remove support for building curl with the gskit TLS library in August 2023.
 - build breakages in this code take weeks or more to get detected
 - fixing gskit code is mostly done "flying blind"
 
+## mingw v1
+
+We remove support for building curl with the original legacy mingw version 1
+in September 2023.
+
+During the deprecation period you can enable the support with the configure
+option `--with-mingw1-deprecated`.
+
+mingw version 1 is old and deprecated software. There are much better and
+still support build environments to use to build curl and other software. For
+example [MinGW-w64](https://www.mingw-w64.org/).
+
 ## space-separated `NOPROXY` patterns
 
 When specifying patterns/domain names for curl that should *not* go through a