As I was unable to reproduce the issue [1] on the development system, but it was all too easy to reproduce on server, I had no choice but to debug on the server. It's not an ideal situation but in this case, as I run the server in question and the appropriate software tools are installed, I figured I might as well debug on the server.
The approach I took is one I've been using for a long time [2]—insert this bit of code:
>
```
volatile int g_debug = 1;
while(g_debug)
;
```
into the proper code path (in this case, the program was crashing in cmd_cgi_post_show() [3], which is the function called when I want to preview a post from the web interface). Then I can submit the data, the web server will spawn mod_blog, and the infinite loop will give me a chance to attach the debugger to it (setting up a fake web environment to debug CGI (Common Gateway Interface) [4] programs is a pain). And from there, it was pretty straightforward to isolate the issue by setting breakpoints and examining memory.
The issue ended up being multiple calls to free() [5], and I suppose the difference in behavior between the development system and server can be attributed to the different versions of the standard C library. Yes, in an ideal world, there would be no difference between the two, but this isn't an ideal world and I have to make do with what I have.
[4] http://en.wikipedia.org/wiki/Common_Gateway_Interface
[5] https://github.com/spc476/mod_blog/commit/3e0662eea842754d8ec9bc922112670f23091384