iostreamlib: add missing cstring header (merge from devbr6, https://trac.osgeo.org/grass/changeset/32668)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@32669 15284696-431f-4ddb-bdfa-cd5b030d7da7

lib/iostream/ami_stream.cc

@@ -25,6 +25,8 @@
 #include <errno.h>
 #include <unistd.h>
 
+#include <cstring>
+
 //#include <ami_stream.h>
 #include <grass/iostream/ami_stream.h>