Fix remaining errors, hopefully compiling now.

Frameworks/libsidplay/sidplay-residfp-code/libsidplayfp/src/builders/resid-builder/resid/wave.cc

@@ -92,7 +92,7 @@ WaveformGenerator::WaveformGenerator()
       // MOS 8580: 2R/R ~ 2.00, correct termination.
       build_dac_table(model_dac[1], 12, 2.00, true);
 
-      class_init = true;
+      g_class_init = true;
     }
   }
 

Frameworks/libsidplay/sidplay-residfp-code/libsidplayfp/src/builders/residfp-builder/residfp/FilterModelConfig.cpp

@@ -24,6 +24,7 @@
 
 #include <cmath>
 #include <cassert>
+#include <mutex>
 
 #include "Integrator.h"
 #include "OpAmp.h"
@@ -90,9 +91,11 @@ const Spline::Point opamp_voltage[OPAMP_SIZE] =
 };
 
 std::unique_ptr<FilterModelConfig> FilterModelConfig::instance(nullptr);
+static std::mutex g_FilterModelConfig_mutex;
 
 FilterModelConfig* FilterModelConfig::getInstance()
 {
+	std::lock_guard<std::mutex> guard(g_FilterModelConfig_mutex);
     if (!instance.get())
     {
         instance.reset(new FilterModelConfig());

Frameworks/libsidplay/sidplay-residfp-code/libsidplayfp/src/builders/residfp-builder/residfp/WaveformCalculator.cpp

@@ -22,16 +22,28 @@
 #include "WaveformCalculator.h"
 
 #include <cmath>
+#include <mutex>
 
 namespace reSIDfp
 {
 
+// Doing it this way somehow prevents race conditions
+
+std::unique_ptr<WaveformCalculator> WaveformCalculator::instance(nullptr);
+static std::mutex g_WaveformCalculator_mutex;
+
 WaveformCalculator* WaveformCalculator::getInstance()
 {
-    static WaveformCalculator instance;
-    return &instance;
+	std::lock_guard<std::mutex> guard(g_WaveformCalculator_mutex);
+	if (!instance.get())
+	{
+		instance.reset(new WaveformCalculator());
+	}
+
+	return instance.get();
 }
 
+
 /**
  * Parameters derived with the Monte Carlo method based on
  * samplings by kevtris. Code and data available in the project repository [1].

Frameworks/libsidplay/sidplay-residfp-code/libsidplayfp/src/builders/residfp-builder/residfp/WaveformCalculator.h

@@ -92,6 +92,9 @@ typedef struct
  */
 class WaveformCalculator
 {
+private:
+	static std::unique_ptr<WaveformCalculator> instance;
+
 private:
     typedef std::map<const CombinedWaveformConfig*, matrix_t> cw_cache_t;