Check for headers which may or may not be available

CMakeLists.txt

 cmake_minimum_required(VERSION 2.4)
 project(postsrsd C)
+include(CheckIncludeFile)
 
 option(GENERATE_SRS_SECRET "Generate a random SRS secret if none exists during install" ON)
 option(USE_APPARMOR "Enable AppArmor profile" OFF)
 find_program(INSSERV insserv DOC "path to insserv executable")
 find_program(CHKCONFIG chkconfig DOC "path to chkconfig executable")
 
+check_include_file(sys/wait.h HAVE_SYS_WAIT_H)
+if(HAVE_SYS_WAIT_H)
+    add_definitions(-DHAVE_SYS_WAIT_H)
+endif()
+check_include_file(wait.h HAVE_WAIT_H)
+if(HAVE_WAIT_H)
+    add_definitions(-DHAVE_WAIT_H)
+endif()
+check_include_file(sys/time.h HAVE_SYS_TIME_H)
+if(HAVE_SYS_TIME_H)
+    add_definitions(-DHAVE_SYS_TIME_H)
+endif()
+check_include_file(time.h HAVE_TIME_H)
+if(HAVE_TIME_H)
+    add_definitions(-DHAVE_TIME_H)
+endif()
+
 if(NOT DEFINED INIT_FLAVOR)
     if(IS_DIRECTORY "${SYSCONF_DIR}/init" AND EXISTS "/lib/init/upstart-job")
         message(STATUS "Detected init flavor: upstart")

postsrsd.c

 #include <pwd.h>
 #include <string.h>
 #include <poll.h>
-#ifdef __APPLE__
-    #include <sys/wait.h>
-#else
-    #include <wait.h>
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+#ifdef HAVE_TIME_H
+#include <time.h>
+#endif
+#ifdef HAVE_SYS_WAIT_H
+#include <sys/wait.h>
+#endif
+#ifdef HAVE_WAIT_H
+#include <wait.h>
 #endif
 #include <syslog.h>