Programs with nested functions will crash when compiled with -pg, e.g.:
----
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
   int x;

void Sub(void)
{
   printf("x=%i",x);
}

   x=random();
   Sub();
   return 0;
}
----
main() tries to pass its %ebp to Sub() in %ecx, but the call to mcount()
will destroy the register. When Sub() tries to access x, the program
will crash.

This is not a DJGPP problem. It's a genuine FSF bug in gcc itself.

(gcc-2.7.2.1 on Linux has the same bug, but egcs-1.0 doesn't).

Looks like someone forgot to tell gcc that %ecx is in use during
the startup phase of a nested function

Update gcc.