Extract subprocessing into separate library

include/linuxdeploy/util/subprocess.h

@@ -0,0 +1,19 @@
+/**
+ * Wrapper for cpp-subprocess. Provides additional convenience functions.
+ */
+
+#pragma once
+
+// library includes
+#include <subprocess.hpp>
+
+namespace linuxdeploy {
+    namespace util {
+        namespace subprocess {
+            using namespace ::subprocess;
+
+            // Reads output channels of existing Popen object into buffers and returns the contents
+            std::pair<std::string, std::string> check_output_error(Popen& proc);
+        }
+    }
+}

include/linuxdeploy/util/util.h

@@ -1,5 +1,6 @@
 // local includes
 #include "misc.h"
+#include "subprocess.h"
 
 // import functions from misc module for convenience
 namespace linuxdeploy {