diff -Naur VirtualBox-5.2.8.orig/src/libs/xpcom18a4/python/src/ErrorUtils.cpp VirtualBox-5.2.8/src/libs/xpcom18a4/python/src/ErrorUtils.cpp
--- VirtualBox-5.2.8.orig/src/libs/xpcom18a4/python/src/ErrorUtils.cpp	2018-02-26 17:05:25.000000000 +0100
+++ VirtualBox-5.2.8/src/libs/xpcom18a4/python/src/ErrorUtils.cpp	2019-04-17 11:45:42.706698000 +0200
@@ -440,7 +440,8 @@
 #if PY_MAJOR_VERSION <= 2
 	char *tempResult = PyString_AsString(obResult);
 #else
-	char *tempResult = PyUnicode_AsUTF8(obResult);
+        /* PyUnicode_AsUTF8() is const char * as of Python 3.7, char * earlier. */
+	const char *tempResult = (const char *)PyUnicode_AsUTF8(obResult);
 #endif
 	result = (char *)PyMem_Malloc(strlen(tempResult)+1);
 	if (result==NULL)