diff --git a/configure.ac b/configure.ac
index 379f23491..5fe32ef33 100644
--- a/configure.ac
+++ b/configure.ac
@@ -172,7 +172,7 @@ AC_ARG_ENABLE(relativeprefix,
         yes) relativeprefix=yes ;;
         no)  relativeprefix=no ;;
         *) AC_MSG_ERROR(bad value ${enableval} for --enable-relativeprefix) ;;
-      esac],[relativeprefix=no])
+      esac],[relativeprefix=guess])
 
 AC_ARG_ENABLE(date,
       [  --enable-date    Use build date in internal version number],
@@ -239,6 +239,11 @@ else
 	package_prefix=${prefix}
 fi
 
+if test "$relativeprefix" = "guess" ; then
+	if test "$mingw_found" = "yes" ; then
+		relativeprefix="yes"
+	fi
+fi
 
 if test "$relativeprefix" = "yes" ; then
 	dnl allow binaries to install everywhere
diff --git a/oRTP b/oRTP
index e16102322..38693cb53 160000
--- a/oRTP
+++ b/oRTP
@@ -1 +1 @@
-Subproject commit e16102322baf5bc6079216c44722f79d1a6202d4
+Subproject commit 38693cb535650fa668ffec8f8daecbeec6289657