From b8eaf5968587c815f63cc21a1baf075f485cde20 Mon Sep 17 00:00:00 2001
From: tsteven4 <tsteven4@users.noreply.github.com>
Date: Fri, 28 Dec 2018 10:14:33 -0700
Subject: [PATCH] add include guard for src/core/optional.h (#290)

---
 csv_util.cc         | 1 +
 src/core/optional.h | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/csv_util.cc b/csv_util.cc
index 84fd98bfa..af959182d 100644
--- a/csv_util.cc
+++ b/csv_util.cc
@@ -32,6 +32,7 @@
 #include "grtcirc.h"
 #include "jeeps/gpsmath.h"
 #include "src/core/logging.h"
+#include "src/core/optional.h"
 #include "strptime.h"
 
 #include <cmath>
diff --git a/src/core/optional.h b/src/core/optional.h
index 0357fb756..72f896b4b 100644
--- a/src/core/optional.h
+++ b/src/core/optional.h
@@ -23,6 +23,9 @@
 // 1. 'gpsbabel_optional::optional' to 'std::optional',
 // 2. 'include "optional.h"' becomes 'include <optional>'.
 
+#ifndef GPSBABEL_OPTIONAL_H_INCLUDED_
+#define GPSBABEL_OPTIONAL_H_INCLUDED_
+
 #if __cplusplus >= 201703L
 #warning "using std::optional"
 #include <optional>
@@ -250,3 +253,4 @@ constexpr bool operator>=(const T& value, const optional<U>& opt)
 } // namespace
 #endif
 
+#endif // GPSBABEL_OPTIONAL_H_INCLUDED_
-- 
2.30.2