Replying to myself, I’d like to give the answer that someone gave me on IRC:
(gdb) apropos pending actions -- Specify the actions to be taken at a tracepoint set breakpoint -- Breakpoint specific settings set breakpoint pending -- Set debugger's behavior regarding pending breakpoints show breakpoint -- Breakpoint specific settings show breakpoint pending -- Show debugger's behavior regarding pending breakpoints
And so set breakpoint pending on does the trick; it is used in cmds.gdb
like e.g.
set breakpoint pending on
break <source file name>:<line number>