SCons: Disable misbehaving MSVC incremental linking

Fixes #77968.

(cherry picked from commit bc1aef88ee)

platform/windows/detect.py

@@ -355,6 +355,9 @@ def configure_msvc(env, vcvars_msvc_config):
         else:
             env.AppendUnique(CCFLAGS=["/MD"])
 
+    # MSVC incremental linking is broken and _increases_ link time (GH-77968).
+    env.Append(LINKFLAGS=["/INCREMENTAL:NO"])
+
     if env["arch"] == "x86_32":
         env["x86_libtheora_opt_vc"] = True