Wrong line number in callstack

Bug Description

The callstack in case of error or whereami return the wrong line number.

--> whereami()
whereami called at line -11 of exec_file
exec     called at line 2 of macro test
test     called at line 17 of exec_file

Steps to reproduce

Create a file that defines a function and uses exec to call another file.

Add the above code at line 12 of the file.

// add some empty lines before the function
function test()
    exec wrong_line.sce
end

test()

Create the wrong_line.sce file and add the following code inside.

whereami()

What is the expected correct behavior?

--> whereami()
whereami called at line 1 of exec_file
exec     called at line 2 of macro test
test     called at line 17 of exec_file

Change the call of whereami()by an error to see the same problem in the callstack.