Add cygwin-release test config.

This tests the flags used to build the cygwin release binaries.

.github/configs

@@ -31,6 +31,9 @@ case "$config" in
 	LIBCRYPTOFLAGS="--without-openssl"
 	TEST_TARGET=t-exec
 	;;
+    cygwin-release)
+	CONFIGFLAGS="--with-libedit --with-xauth=/usr/bin/xauth --disable-strip --with-security-key-builtin"
+	;;
    clang-12-Werror)
 	CC="clang-12"
 	# clang's implicit-fallthrough requires that the code be annotated with

.github/workflows/selfhosted.yml

@@ -64,6 +64,7 @@ jobs:
           - { os: sol11,  configs: pam-krb5 }
           - { os: sol11,  configs: sol64 }
           # - { os: sol11,  configs: sol64-pam }
+          - { os: win10,  configs: cygwin-release }
     steps:
     - uses: actions/checkout@v2
     - name: autoreconf