string: ensure string included

Latest upstream yocto appears to have removed a free include of string.
This is causing compile failures for files which do not include it
properly.

Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
Change-Id: Ie93f251b00db4d4a543b361262fad2201923e2c5
diff --git a/mslverify/util.hpp b/mslverify/util.hpp
index ae83006..2d20392 100644
--- a/mslverify/util.hpp
+++ b/mslverify/util.hpp
@@ -5,6 +5,7 @@
 #include <phosphor-logging/log.hpp>
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/message.hpp>
+#include <string>
 #include <xyz/openbmc_project/Common/error.hpp>
 
 namespace util
diff --git a/src/data_types.hpp b/src/data_types.hpp
index a022fea..81bb8cb 100644
--- a/src/data_types.hpp
+++ b/src/data_types.hpp
@@ -4,6 +4,7 @@
 
 #include <experimental/any>
 #include <sdbusplus/message.hpp>
+#include <string>
 
 namespace any_ns = std::experimental;
 
diff --git a/src/elog.hpp b/src/elog.hpp
index d98984c..6e46b77 100644
--- a/src/elog.hpp
+++ b/src/elog.hpp
@@ -5,6 +5,7 @@
 #include <phosphor-logging/elog-errors.hpp>
 #include <phosphor-logging/elog.hpp>
 #include <sdbusplus/exception.hpp>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/event.hpp b/src/event.hpp
index 2116977..7ce764b 100644
--- a/src/event.hpp
+++ b/src/event.hpp
@@ -5,6 +5,7 @@
 
 #include <phosphor-logging/log.hpp>
 #include <sstream>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/event_entry.hpp b/src/event_entry.hpp
index 899e5ec..28a6338 100644
--- a/src/event_entry.hpp
+++ b/src/event_entry.hpp
@@ -5,6 +5,7 @@
 
 #include <sdbusplus/bus.hpp>
 #include <sdbusplus/server/object.hpp>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/event_manager.hpp b/src/event_manager.hpp
index a4ccf18..c114000 100644
--- a/src/event_manager.hpp
+++ b/src/event_manager.hpp
@@ -6,6 +6,7 @@
 #include <memory>
 #include <queue>
 #include <sdbusplus/bus.hpp>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/event_serialize.hpp b/src/event_serialize.hpp
index d331950..bb6f22f 100644
--- a/src/event_serialize.hpp
+++ b/src/event_serialize.hpp
@@ -5,6 +5,7 @@
 #include "event_entry.hpp"
 
 #include <experimental/filesystem>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/format.hpp b/src/format.hpp
index 32a85f8..fe8565b 100644
--- a/src/format.hpp
+++ b/src/format.hpp
@@ -2,6 +2,8 @@
 
 #include "data_types.hpp"
 
+#include <string>
+
 namespace phosphor
 {
 namespace dbus
diff --git a/src/journal.hpp b/src/journal.hpp
index e69a709..29d01d1 100644
--- a/src/journal.hpp
+++ b/src/journal.hpp
@@ -4,6 +4,7 @@
 #include "format.hpp"
 
 #include <phosphor-logging/log.hpp>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/method.hpp b/src/method.hpp
index f8f8f51..1399531 100644
--- a/src/method.hpp
+++ b/src/method.hpp
@@ -4,6 +4,7 @@
 
 #include <experimental/tuple>
 #include <phosphor-logging/log.hpp>
+#include <string>
 
 namespace phosphor
 {
diff --git a/src/pathwatch.hpp b/src/pathwatch.hpp
index b0b8b42..25fd6de 100644
--- a/src/pathwatch.hpp
+++ b/src/pathwatch.hpp
@@ -10,6 +10,8 @@
 #include "data_types.hpp"
 #include "watch.hpp"
 
+#include <string>
+
 namespace phosphor
 {
 namespace dbus
diff --git a/src/propertywatch.hpp b/src/propertywatch.hpp
index ecb8e9c..84b6af7 100644
--- a/src/propertywatch.hpp
+++ b/src/propertywatch.hpp
@@ -11,6 +11,8 @@
 #include "filters.hpp"
 #include "watch.hpp"
 
+#include <string>
+
 namespace phosphor
 {
 namespace dbus
diff --git a/src/propertywatchimpl.hpp b/src/propertywatchimpl.hpp
index 048050e..60aff5c 100644
--- a/src/propertywatchimpl.hpp
+++ b/src/propertywatchimpl.hpp
@@ -6,6 +6,7 @@
 
 #include <sdbusplus/bus/match.hpp>
 #include <sdbusplus/message.hpp>
+#include <string>
 #include <vector>
 
 namespace phosphor
diff --git a/src/resolve_errors.hpp b/src/resolve_errors.hpp
index c58dc7d..979261a 100644
--- a/src/resolve_errors.hpp
+++ b/src/resolve_errors.hpp
@@ -1,6 +1,8 @@
 #pragma once
 #include "callback.hpp"
 
+#include <string>
+
 namespace phosphor
 {
 namespace dbus
diff --git a/src/sdbusplus.hpp b/src/sdbusplus.hpp
index 96a8903..02c530d 100644
--- a/src/sdbusplus.hpp
+++ b/src/sdbusplus.hpp
@@ -7,6 +7,7 @@
 #include <sdbusplus/bus/match.hpp>
 #include <sdbusplus/exception.hpp>
 #include <sdbusplus/message.hpp>
+#include <string>
 
 struct Loop;