diff --git a/virtuoso-opensource-6.1.0-external_iodbc.patch b/virtuoso-opensource-6.1.0-external_iodbc.patch
deleted file mode 100644
index c3b3552..0000000
--- a/virtuoso-opensource-6.1.0-external_iodbc.patch
+++ /dev/null
@@ -1,21 +0,0 @@
-diff -up virtuoso-opensource-6.1.0/configure.in.external_iodbc virtuoso-opensource-6.1.0/configure.in
---- virtuoso-opensource-6.1.0/configure.in.external_iodbc	2010-02-03 14:49:18.000000000 -0600
-+++ virtuoso-opensource-6.1.0/configure.in	2010-02-04 08:16:51.265605024 -0600
-@@ -1833,7 +1833,7 @@ AC_DEFINE(NO_UDBC_SDK,1, [Define if usin
- #
- if test "x$virt_do_iodbc" = "xyes"
- then
--    iodbc_CPPFLAGS="-I$virt_iodbc_dir/include"
-+    iodbc_CPPFLAGS=`pkg-config --cflags libiodbc`
- 
-     saved_CPPFLAGS="$CPPFLAGS"
-     CPPFLAGS="$iodbc_CPPFLAGS $CPPFLAGS"
-@@ -1842,7 +1842,7 @@ then
- 
-     ccincl="$iodbc_CPPFLAGS $ccincl"
- 
--    iodbc_LDFLAGS="-L$virt_iodbc_dir/lib -liodbc -liodbcinst $LIBDL"
-+    iodbc_LDFLAGS=`pkg-config --libs libiodbc`
-     AC_CHECK_LIB(iodbc, SQLTables,
- 		 [
- 		  virt_do_iodbc="yes"
diff --git a/virtuoso-opensource.spec b/virtuoso-opensource.spec
index 60a8778..9f45ac7 100644
--- a/virtuoso-opensource.spec
+++ b/virtuoso-opensource.spec
@@ -9,7 +9,7 @@
 Name:    virtuoso-opensource
 Epoch:   1
 Version: 6.1.6
-Release: 3%{?dist}
+Release: 4%{?dist}
 Summary: A high-performance object-relational SQL database
 
 Group:   Applications/Databases
@@ -25,8 +25,6 @@ Source0: http://downloads.sourceforge.net/virtuoso/virtuoso-opensource-%{version
 BuildRoot: %(mktemp -ud %{_tmppath}/%{name}-%{version}-%{release}-XXXXXX)
 
 ## Upstreamable patches
-# based on http://svn.mandriva.com/cgi-bin/viewvc.cgi/packages/cooker/virtuoso-opensource/current/SOURCES/virtuoso-opensource-6.1.0-extern-iodbc.patch
-Patch51: virtuoso-opensource-6.1.0-external_iodbc.patch
 Patch52: virtuoso-opensource-6.1.0-nodemos_buildfix.patch
 Patch53: virtuoso-opensource-6.1.4-no_strip.patch
 
@@ -37,6 +35,7 @@ BuildRequires: bison
 BuildRequires: flex
 BuildRequires: gawk
 BuildRequires: gperf
+BuildRequires: pkgconfig
 %if 0%{?fedora}
 BuildRequires: htmldoc
 %endif
@@ -98,8 +97,6 @@ Requires: %{name} = %{?epoch:%{epoch}:}%{version}-%{release}
 %prep
 %setup -q -n virtuoso-opensource-%{version}
 
-#patch51 -p1 -b .external_iodbc
-
 %if 0%{?_disable_all_vads:1}
 %patch52 -p1 -b .nodemos_buildfix
 %endif
@@ -220,6 +217,9 @@ rm -rf %{buildroot}
 
 
 %changelog
+* Tue May 28 2013 Lukáš Tinkl <ltinkl@redhat.com> - 1:6.1.6-4
+- drop obsolete and unused (external iodbc) patch
+
 * Fri Feb 15 2013 Fedora Release Engineering <rel-eng@lists.fedoraproject.org> - 1:6.1.6-3
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_19_Mass_Rebuild