I am running emacs 24.3.1. I am not sure this is specific to mavericks. I think it occurred on Mountain Lion as well.

When running emacs in a window, suspend-emacs really shouldn't do anything I suppose. But what it does do on my system is crash:

Exception Type:  EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000

Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0   libsystem_kernel.dylib        	0x00007fff84007292 __kill + 10
1   org.gnu.Emacs                 	0x000000010009ea21 terminate_due_to_signal + 145 (emacs.c:344)
2   org.gnu.Emacs                 	0x00000001000ba8f3 emacs_abort + 19
3   org.gnu.Emacs                 	0x000000010017ef3b ns_term_shutdown + 123
4   org.gnu.Emacs                 	0x000000010009ec5a shut_down_emacs + 298 (emacs.c:1931)
5   org.gnu.Emacs                 	0x000000010009e9e7 terminate_due_to_signal + 87 (emacs.c:329)
6   org.gnu.Emacs                 	0x00000001000ba8f3 emacs_abort + 19
7   org.gnu.Emacs                 	0x00000001000ae565 Fsuspend_emacs + 629
8   org.gnu.Emacs                 	0x0000000100117e3d Ffuncall + 1037 (eval.c:2778)
9   org.gnu.Emacs                 	0x0000000100112d2f Fcall_interactively + 5167 (callint.c:854)
10  org.gnu.Emacs                 	0x0000000100117e61 Ffuncall + 1073 (eval.c:2785)
11  org.gnu.Emacs                 	0x0000000100118375 call3 + 53 (eval.c:2603)
12  org.gnu.Emacs                 	0x00000001000a21a1 command_loop_1 + 1345 (keyboard.c:1595)
13  org.gnu.Emacs                 	0x000000010011648c internal_condition_case + 284 (eval.c:1290)
14  org.gnu.Emacs                 	0x00000001000b303e command_loop_2 + 62 (keyboard.c:1168)
15  org.gnu.Emacs                 	0x0000000100115f15 internal_catch + 213 (eval.c:1060)
16  org.gnu.Emacs                 	0x00000001000a12ae recursive_edit_1 + 334 (keyboard.c:1148)
17  org.gnu.Emacs                 	0x00000001000a13fa Frecursive_edit + 250 (keyboard.c:844)
18  org.gnu.Emacs                 	0x00000001000a0206 main + 5446 (emacs.c:1528)
19  libdyld.dylib                 	0x00007fff8a4305fd start + 1

I looked at the code and am not sure why abort is being called, so not sure what say about that.

JP