bug in EN_set_odbc3 macro

Hi,

I found that the EN_set_odbc3 macro in environ.h seems to be
wrong. It's defined as:

#define EN_set_odbc3(env) (env->flag &= EN_OV_ODBC2)

There should probably be a ~ in there too:

#define EN_set_odbc3(env) (env->flag &= ~EN_OV_ODBC2)


Greetings,

Tomas