[PATCH gpgmepp] add missing header

[tachalorah at proton.me]

* src/util: add missing <iterator> for std::back_inserter

Fixes missing std::back_inserter when building with clang++
-D_LIBCPP_REMOVE_TRANSITIVE_INCLUDES.
---
 src/util.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/util.cpp b/src/util.cpp
index 6cbc9ba..77fac5b 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -28,6 +28,7 @@
 #include "util.h"

 #include <functional>
+#include <iterator>

 #include <cstring>

--
2.54.0