Thank you for answer.
Compiling with difmod.c is ok, but linking now with libcrypto.a and msvcrt.lib conflicts. One only error message:
POLINK: error: Symbol '_fclose' is multiply defined: 'msvcrt.lib(msvcrt.dll)' and 'crt.lib(fclose.obj)'.
Linking with libeya32.lib resolves all externals. But for run it is nessesary also to include libeay32.dll in windows directory.
To avoid to place libeay32.dll in windows or working directory of the exe, I converted libeay32.dll with the import library libeay32.lib to the static library libeay32dll.lib (by means of DLL to LIB 3.0,
http://www.binary-soft.com/).
With the linker parameters
-subsystem:windows -machine:x86 -map -release kernel32.lib user32.lib gdi32.lib advapi32.lib wsock32.lib libeay32dll.lib
the exe was built successful.