consolidate sys_execve() prototype

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 727f0cd7..2779009 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -837,6 +837,9 @@
 		current_pt_regs())
 #endif
 
+asmlinkage long sys_execve(const char __user *filename,
+		const char __user *const __user *argv,
+		const char __user *const __user *envp);
 
 asmlinkage long sys_perf_event_open(
 		struct perf_event_attr __user *attr_uptr,