diff --git a/include/dsp/ctcssdetector.h b/include/dsp/ctcssdetector.h
index 11e6cc872..e3799c07c 100644
--- a/include/dsp/ctcssdetector.h
+++ b/include/dsp/ctcssdetector.h
@@ -25,7 +25,7 @@ public:
 
     // setup the basic parameters and coefficients
     void setCoefficients(
-    		int N,            // the algorithm "block"  size
+    		int zN,            // the algorithm "block"  size
 			int SampleRate);  // input signal sample rate
 
     // set the detection threshold
diff --git a/include/util/gleshelp.h b/include/util/gleshelp.h
new file mode 100644
index 000000000..b027e7715
--- /dev/null
+++ b/include/util/gleshelp.h
@@ -0,0 +1,33 @@
+///////////////////////////////////////////////////////////////////////////////////
+// Copyright (C) 2015 Edouard Griffiths, F4EXB.                                  //
+//                                                                               //
+// This is a header file to help migrate to GL ES 2.0                            //
+//                                                                               //
+// This program is free software; you can redistribute it and/or modify          //
+// it under the terms of the GNU General Public License as published by          //
+// the Free Software Foundation as version 3 of the License, or                  //
+//                                                                               //
+// This program is distributed in the hope that it will be useful,               //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the                  //
+// GNU General Public License V3 for more details.                               //
+//                                                                               //
+// You should have received a copy of the GNU General Public License             //
+// along with this program. If not, see <http://www.gnu.org/licenses/>.          //
+///////////////////////////////////////////////////////////////////////////////////
+
+#ifndef INCLUDE_UTIL_GLESHELP_H_
+#define INCLUDE_UTIL_GLESHELP_H_
+
+#define GLdouble     GLfloat
+#define GL_CLAMP     GL_CLAMP_TO_EDGE
+#define glClearDepth glClearDepthf
+#define glOrtho      glOrthof
+#define glFrustum    glFrustumf
+
+#define glColor4fv(a) glColor4f(a[0], a[1], a[2], a[3])
+#define glColor3fv(a) glColor4f(a[0], a[1], a[2], 1.0f)
+#define glColor3f(a,b,c) glColor4f(a, b, c, 1.0f
+
+
+#endif /* INCLUDE_UTIL_GLESHELP_H_ */
diff --git a/sdrbase/dsp/afsquelch.cpp b/sdrbase/dsp/afsquelch.cpp
index 474d7b189..453c1f7fe 100644
--- a/sdrbase/dsp/afsquelch.cpp
+++ b/sdrbase/dsp/afsquelch.cpp
@@ -82,9 +82,9 @@ AFSquelch::~AFSquelch()
 }
 
 
-void AFSquelch::setCoefficients(int _N, unsigned int nbAvg, int _samplerate, int _samplesAttack, int _samplesDecay )
+void AFSquelch::setCoefficients(int N, unsigned int nbAvg, int _samplerate, int _samplesAttack, int _samplesDecay )
 {
-	m_N = _N;                   // save the basic parameters for use during analysis
+	m_N = N;                   // save the basic parameters for use during analysis
 	m_nbAvg = nbAvg;
 	m_sampleRate = _samplerate;
 	m_samplesAttack = _samplesAttack;
diff --git a/sdrbase/dsp/ctcssdetector.cpp b/sdrbase/dsp/ctcssdetector.cpp
index c31193101..2fdc786ab 100644
--- a/sdrbase/dsp/ctcssdetector.cpp
+++ b/sdrbase/dsp/ctcssdetector.cpp
@@ -92,9 +92,9 @@ CTCSSDetector::~CTCSSDetector()
 }
 
 
-void CTCSSDetector::setCoefficients(int _N, int _samplerate )
+void CTCSSDetector::setCoefficients(int zN, int _samplerate )
 {
-	N = _N;                   // save the basic parameters for use during analysis
+	N = zN;                   // save the basic parameters for use during analysis
 	sampleRate = _samplerate;
 
 	// for each of the frequencies (tones) of interest calculate
diff --git a/sdrbase/gui/glscope.cpp b/sdrbase/gui/glscope.cpp
index 12d4b47c4..1ce678139 100644
--- a/sdrbase/gui/glscope.cpp
+++ b/sdrbase/gui/glscope.cpp
@@ -1,3 +1,4 @@
+#include "util/gleshelp.h"
 #include <QPainter>
 #include <QMouseEvent>
 #include "gui/glscope.h"
diff --git a/sdrbase/gui/glspectrum.cpp b/sdrbase/gui/glspectrum.cpp
index c9c870aaa..4c56578a7 100644
--- a/sdrbase/gui/glspectrum.cpp
+++ b/sdrbase/gui/glspectrum.cpp
@@ -18,6 +18,8 @@
 #ifdef USE_SIMD
 #include <immintrin.h>
 #endif
+
+#include "util/gleshelp.h"
 #include <QMouseEvent>
 #include "gui/glspectrum.h"