Version numbers for libtasn1.h

Description of problem:

It's not easy to check for a certain version of libtasn1.h since the only version information is

#define ASN1_VERSION "4.13"

How to check for major/minor via C preprocessor (#if ...) ?

Version of libtasn1 used:

4.13

Suggestion

Use the same standards mechanism as other libraries do, e.g. gnutls.