push NULL on stack instead of 0; sizeof(NULL) > sizeof(0) in MinGW64,…

[fdik-win]

… which results in an access violation when pulling.

When compiling asn1c with MinGW64 out of MSys64 the resulting asn1c.exe crashes with an access violation while parsing. The reason is the usage of va_arg libasn1compiler/asn1c_misc.c line 72. This pulls until a null value is read.

On different occations (int) 0 is being pushed on the stack instead of (intptr_t) NULL. Because sizeof(int) < sizeof(intptr_t) with this compiler too less data is pushed onto the stack, because what is being pushed is a char *, and sizeof(char *) == sizeof(intptr_t). Hence the access violation.

This patch fixes a possible problem on all platforms, and at least on MinGW64 a real problem.

The patch is relative to v0.9.28. It would be good to see a v0.9.29 coming with this, being compatible to v0.9.28 otherwise.

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