bsd-user: save the path to the qemu emulator

Save the path to the qemu emulator. This will be used later when we have
a more complete implementation of exec.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Acked-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Kyle Evans <kevans@FreeBSD.org>

bsd-user/qemu.h

@@ -207,6 +207,7 @@ void mmap_fork_start(void);
 void mmap_fork_end(int child);
 
 /* main.c */
+extern char qemu_proc_pathname[];
 extern unsigned long x86_stack_size;
 
 /* user access */