SignerFreeSignerContext function missing

[virzak]

Seems to be missing

https://docs.microsoft.com/en-us/windows/win32/seccrypto/signerfreesignercontext

[timsneath]

That's because of this note in the docs:

This function has no associated header file or import library. To call this function, you must create a user-defined header file and use the LoadLibrary and GetProcAddress functions to dynamically link to Mssign32.dll.

[mikebattista]

This whole family of APIs needs to be manually defined if they aren't in the headers. I defined SignerFreeSignerContext as an example with 5295205 if someone else wants to run with it and define the rest.