Merge branch 'master' of https://github.com/coelckers/gzdoom

src/gl/system/gl_interface.cpp

@@ -66,11 +66,36 @@ static void CollectExtensions()
 	int max = 0;
 	glGetIntegerv(GL_NUM_EXTENSIONS, &max);
 
-	for(int i = 0; i < max; i++)
+	if (0 == max)
+	{
+		// Try old method to collect extensions
+		const char *supported = (char *)glGetString(GL_EXTENSIONS);
+
+		if (nullptr != supported)
+		{
+			char *extensions = new char[strlen(supported) + 1];
+			strcpy(extensions, supported);
+
+			char *extension = strtok(extensions, " ");
+
+			while (extension)
+			{
+				m_Extensions.Push(FString(extension));
+				extension = strtok(nullptr, " ");
+			}
+
+			delete [] extensions;
+		}
+	}
+	else
+	{
+		// Use modern method to collect extensions
+		for (int i = 0; i < max; i++)
 		{
 			extension = (const char*)glGetStringi(GL_EXTENSIONS, i);
 			m_Extensions.Push(FString(extension));
 		}
+	}
 }
 
 //==========================================================================