The MIT licence provides that
Permission is hereby granted ... to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software ... subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
Note the absence of any ...
To paraphrase the quote from the FSF given in the answer by JNic:
The license of the interpreter itself is of no concern. The interpreter and the software executed by it are independent works as far as copyright is concerned and their licenses don't affect each other.
If you want to keep your application proprietary, you cannot use any GPL-licensed library ...
If Microsoft was mixed up with sublicensing of others products which they bundled into SDK you are in trouble even without any notices in files headers. Like buying stolen doesn't legalize ownership.
You have to read EULA of SDK. It might point to 3rd parties and their conditions.
It it requerment in USA to mark copyright rights in each work. In Europe is ...
You have actually a 3rd possibility to structure your code:
+--- your code
+-+- 3rd party
|--- project A
|--- project B
This form is used in several projects where files from 3rd-party libraries are included for simplification or where maybe some small custom adjustments to interfaces need be done or a very specific version is ...
What is the situation when the end user has to include this code explicitly? Is the exception still triggered or this automatically force him to use GPLv3?
I believe the linking exception will remain in effect, as long as neither you nor the end-user rely on the specific implementation in those files, but only that they provide a implementation for a set of ...