Make busybox more portable

[Sean MacLennan]

Move some distro specific include files into the appropriate #ifdef
blocks to make the code more portable.

Signed-off-by: Sean MacLennan <seanm at seanm.ca>
---
diff --git a/libbb/missing_syscalls.c b/libbb/missing_syscalls.c
index 0934128..36bb9f1 100644
--- a/libbb/missing_syscalls.c
+++ b/libbb/missing_syscalls.c
@@ -7,10 +7,11 @@
 //kbuild:lib-y += missing_syscalls.o
 
 /*#include <linux/timex.h> - for struct timex, but may collide with <time.h> */
-#include <sys/syscall.h>
 #include "libbb.h"
 
 #if defined(ANDROID) || defined(__ANDROID__)
+#include <sys/syscall.h>
+
 pid_t getsid(pid_t pid)
 {
 	return syscall(__NR_getsid, pid);
diff --git a/libbb/vfork_daemon_rexec.c b/libbb/vfork_daemon_rexec.c
index 6125983..abb01e9 100644
--- a/libbb/vfork_daemon_rexec.c
+++ b/libbb/vfork_daemon_rexec.c
@@ -14,7 +14,6 @@
  *
  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
-#include <sys/prctl.h>
 #ifndef PR_SET_NAME
 #define PR_SET_NAME 15
 #endif
@@ -29,6 +28,8 @@
 #define NOEXEC_SUPPORT ((NUM_APPLETS > 1) && (ENABLE_FEATURE_PREFER_APPLETS || ENABLE_FEATURE_SH_STANDALONE))
 
 #if defined(__linux__) && (NUM_APPLETS > 1)
+#include <sys/prctl.h>
+
 void FAST_FUNC set_task_comm(const char *comm)
 {
 	/* okay if too long (truncates) */