include what you use: errno.h and string.h in base/

Adding some missing errno.h includes for errno and
string.h for strerror in base/

Review URL: https://codereview.chromium.org/1434533004

Cr-Commit-Position: refs/heads/master@{#358477}

base/memory/shared_memory_mac.cc

@@ -4,6 +4,7 @@
 
 #include "base/memory/shared_memory.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <mach/mach_vm.h>
 #include <sys/mman.h>

base/memory/shared_memory_posix.cc

@@ -4,6 +4,7 @@
 
 #include "base/memory/shared_memory.h"
 
+#include <errno.h>
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>

base/process/kill_mac.cc

@@ -4,6 +4,7 @@
 
 #include "base/process/kill.h"
 
+#include <errno.h>
 #include <signal.h>
 #include <sys/event.h>
 #include <sys/types.h>

base/process/kill_posix.cc

@@ -4,6 +4,7 @@
 
 #include "base/process/kill.h"
 
+#include <errno.h>
 #include <signal.h>
 #include <sys/types.h>
 #include <sys/wait.h>

base/process/process_iterator_freebsd.cc

@@ -4,6 +4,7 @@
 
 #include "base/process/process_iterator.h"
 
+#include <errno.h>
 #include <sys/types.h>
 #include <sys/sysctl.h>
 #include <unistd.h>

base/process/process_posix.cc

@@ -4,6 +4,7 @@
 
 #include "base/process/process.h"
 
+#include <errno.h>
 #include <sys/resource.h>
 #include <sys/wait.h>
 

base/strings/safe_sprintf.cc

@@ -4,6 +4,9 @@
 
 #include "base/strings/safe_sprintf.h"
 
+#include <errno.h>
+#include <string.h>
+
 #include <limits>
 
 #if !defined(NDEBUG)