Line number of segmentation fault

I don't know of a gcc option, but you should be able to run the application with gdb and then when it crashes, type where to take a look at the stack when it exited, which should get you close.

$ gdb blah
(gdb) run
(gdb) where

Edit for completeness:

You should also make sure to build the application with debug flags on using the -g gcc option to include line numbers in the executable.

Another option is to use the bt (backtrace) command.

Here's a complete shell/gdb session

$ gcc -ggdb myproj.c
$ gdb a.out
gdb> run --some-option=foo --other-option=bar
(gdb will say your program hit a segfault)
gdb> bt
(gdb prints a stack trace)
gdb> q
[are you sure, your program is still running]? y
$ emacs myproj.c # heh, I know what the error is now...

Happy hacking :-)