Display the message tag with each warning message.
With-errtags=yes, the compiler’s internal error tag name will appear along with warning messages. -errtags alone is equivalent to -errtags=yes.
The default is not to display the tag (-errtags=no).
demo% f95 -errtags ink.f ink.f: MAIN: "ink.f", line 11: Warning: local variable "i" never used (WDECL_LOCAL_NOTUSED)