It looks like the problem is that SDL2 isn’t properly signed. There’s a ticket to fix the issue at https://bugzilla.libsdl.org/show_bug.cgi?id=2058.
When you spawn an application from Xcode 5 with lldb, Xcode loads a plugin that will inspect modules your application loads, presumably to give you insight into your program. Xcode is set up to crash if it reads from a page that is backed by an invalid signature. Because SDL2 isn’t properly signed, when Xcode 5 attempts to examine the SDL2 library, it will read from an invalid page, and crash. You get a clue that this is happening by the following line in your crash report above:
Exception Type: EXC_BAD_ACCESS (Code Signature Invalid)
To see for yourself that SDL isn’t properly signed, execute the following command from the folder where SDL2 resides:
$ codesign -vvvv SDL2
SDL2: invalid signature (code or signature have been modified)
In architecture: x86_64
If you don’t want to build your own version of SDL2 (the solution that’s mentioned above), you can update the signature to make it correct:
$ codesign -f -s - SDL2
SDL2: replacing existing signature
And to verify that the new signature is good:
$ codesign -vvvv SDL2
SDL2: valid on disk
SDL2: satisfies its Designated Requirement
Note that doing this as a workaround is risky from a security standpoint, as I’m not sure why the signature is invalid.