nixpkgs/pkgs/applications/science/astronomy/xplanet/gcc6.patch

diff --git c/src/libannotate/addArcs.cpp i/src/libannotate/addArcs.cpp
index 2ee06c0..0ff5478 100644
--- c/src/libannotate/addArcs.cpp
+++ i/src/libannotate/addArcs.cpp
@@ -258,7 +258,7 @@ addArcs(PlanetProperties *planetProperties, Planet *planet,
         {
             ifstream inFile(arcFile.c_str());
             char *line = new char[MAX_LINE_LENGTH];
-            while (inFile.getline (line, MAX_LINE_LENGTH, '\n') != NULL)
+            while (inFile.getline (line, MAX_LINE_LENGTH, '\n'))
                 readArcFile(line, planet, view, projection,
                             planetProperties, annotationMap);
             
@@ -292,7 +292,7 @@ addArcs(View *view, multimap<double, Annotation *> &annotationMap)
         {
             ifstream inFile(arcFile.c_str());
             char *line = new char[256];
-            while (inFile.getline (line, 256, '\n') != NULL)
+            while (inFile.getline (line, 256, '\n'))
                 readArcFile(line, NULL, view, NULL, NULL, annotationMap);
 
             inFile.close();
diff --git c/src/libannotate/addMarkers.cpp i/src/libannotate/addMarkers.cpp
index 6a8a835..b35d820 100644
--- c/src/libannotate/addMarkers.cpp
+++ i/src/libannotate/addMarkers.cpp
@@ -423,7 +423,7 @@ addMarkers(PlanetProperties *planetProperties, Planet *planet,
         {
             ifstream inFile(markerFile.c_str());
             char *line = new char[MAX_LINE_LENGTH];
-            while (inFile.getline (line, MAX_LINE_LENGTH, '\n') != NULL)
+            while (inFile.getline (line, MAX_LINE_LENGTH, '\n'))
             {
                 unsigned char color[3];
                 memcpy(color, planetProperties->MarkerColor(), 3);
@@ -469,7 +469,7 @@ addMarkers(View *view, const int width, const int height,
         {
             ifstream inFile(markerFile.c_str());
             char *line = new char[MAX_LINE_LENGTH];
-            while (inFile.getline (line, MAX_LINE_LENGTH, '\n') != NULL)
+            while (inFile.getline (line, MAX_LINE_LENGTH, '\n'))
             {
                 unsigned char color[3];
                 memcpy(color, options->Color(), 3);
diff --git c/src/libannotate/addSatellites.cpp i/src/libannotate/addSatellites.cpp
index 2634339..c9ff0b0 100644
--- c/src/libannotate/addSatellites.cpp
+++ i/src/libannotate/addSatellites.cpp
@@ -488,10 +488,10 @@ loadSatelliteVector(PlanetProperties *planetProperties)
         {
             ifstream inFile(tleFile.c_str());
             char lines[3][80];
-            while (inFile.getline(lines[0], 80) != NULL)
+            while (inFile.getline(lines[0], 80))
             {
-                if ((inFile.getline(lines[1], 80) == NULL) 
-                    || (inFile.getline(lines[2], 80) == NULL))
+                if ((inFile.getline(lines[1], 80))
+                    || (inFile.getline(lines[2], 80)))
                 {
                     ostringstream errStr;
                     errStr << "Malformed TLE file (" << tleFile << ")?\n";
@@ -542,7 +542,7 @@ addSatellites(PlanetProperties *planetProperties, Planet *planet,
         {
             ifstream inFile(satFile.c_str());
             char *line = new char[MAX_LINE_LENGTH];
-            while (inFile.getline (line, MAX_LINE_LENGTH, '\n') != NULL)
+            while (inFile.getline (line, MAX_LINE_LENGTH, '\n'))
                 readSatelliteFile(line, planet, view, projection,
                                   planetProperties, annotationMap);
             
diff --git c/src/libmultiple/RayleighScattering.cpp i/src/libmultiple/RayleighScattering.cpp
index d885173..7c25c1c 100644
--- c/src/libmultiple/RayleighScattering.cpp
+++ i/src/libmultiple/RayleighScattering.cpp
@@ -369,7 +369,7 @@ RayleighScattering::readConfigFile(string configFile)
 
     diskTemplate_.clear();
     limbTemplate_.clear();
-    while (inFile.getline(line, MAX_LINE_LENGTH, '\n') != NULL)
+    while (inFile.getline(line, MAX_LINE_LENGTH, '\n'))
     {
         int i = 0;
         while (isDelimiter(line[i]))
@@ -439,7 +439,7 @@ RayleighScattering::readBlock(ifstream &inFile,
     values.clear();
 
     char line[MAX_LINE_LENGTH];
-    while (inFile.getline(line, MAX_LINE_LENGTH, '\n') != NULL)
+    while (inFile.getline(line, MAX_LINE_LENGTH, '\n'))
     {
         int i = 0;
         while (isDelimiter(line[i]))
@@ -470,7 +470,7 @@ RayleighScattering::readValue(ifstream &inFile,
                               double &value)
 {
     char line[MAX_LINE_LENGTH];
-    while (inFile.getline(line, MAX_LINE_LENGTH, '\n') != NULL)
+    while (inFile.getline(line, MAX_LINE_LENGTH, '\n'))
     {
         int i = 0;
         while (isDelimiter(line[i]))
diff --git c/src/libmultiple/drawStars.cpp i/src/libmultiple/drawStars.cpp
index ff07c49..22e41a0 100644
--- c/src/libmultiple/drawStars.cpp
+++ i/src/libmultiple/drawStars.cpp
@@ -41,7 +41,7 @@ drawStars(DisplayBase *display, View *view)
     ifstream inFile(starMap.c_str());
 
     char line[MAX_LINE_LENGTH];
-    while (inFile.getline(line, MAX_LINE_LENGTH, '\n') != NULL)
+    while (inFile.getline(line, MAX_LINE_LENGTH, '\n'))
     {
         if (line[0] == '#') continue;
 
diff --git c/src/readConfig.cpp i/src/readConfig.cpp
index cc1964f..2946690 100644
--- c/src/readConfig.cpp
+++ i/src/readConfig.cpp
@@ -550,7 +550,7 @@ readConfigFile(string configFile, PlanetProperties *planetProperties[])
 
         ifstream inFile(configFile.c_str());
         char *line = new char[256];
-        while (inFile.getline(line, 256, '\n') != NULL)
+        while (inFile.getline(line, 256, '\n'))
             readConfig(line, planetProperties);
         
         // This condition will only be true if [default] is the only