test/recipes/90-test_shlibload.t needs $target{shared_extension}

We therefore must add defaults.
Reviewed-by: NViktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7626)

(cherry picked from commit 45cdae1c7c93fe7ef2a981da4c36c3b8cb09e855)

Configurations/00-base-templates.conf

@@ -102,6 +102,8 @@ my %targets=(
                                      ? "ranlib" : "" },
         RC              => "windres",
 
+        shared_extension => ".so",
+
         build_scheme    => [ "unified", "unix" ],
         build_file      => "Makefile",
     },
@@ -142,6 +144,8 @@ my %targets=(
         mtinflag        => "-manifest ",
         mtoutflag       => "-outputresource:",
 
+        shared_extension => ".dll",
+
         build_file      => "makefile",
         build_scheme    => [ "unified", "windows" ],
     },
@@ -160,6 +164,8 @@ my %targets=(
                     return [ @incs ];
                 }),
 
+        shared_extension => ".exe",
+
         build_file       => "descrip.mms",
         build_scheme     => [ "unified", "VMS" ],
     },