Fix undefined behaviors (#14365)

* Initialize member `floats` in ContentFeatures

* Do not assign big double to u32

* Do not assign negative floating point number to unsigned integer

src/mapgen/mg_biome.cpp

@@ -297,7 +297,11 @@ Biome *BiomeGenOriginal::calcBiomeFromNoise(float heat, float humidity, v3s16 po
 	// Carefully tune pseudorandom seed variation to avoid single node dither
 	// and create larger scale blending patterns similar to horizontal biome
 	// blend.
-	const u64 seed = pos.Y + (heat + humidity) * 0.9f;
+	// The calculation can be a negative floating point number, which is an
+	// undefined behavior if assigned to unsigned integer. Cast the result
+	// into signed integer before it is casted into unsigned integer to
+	// eliminate the undefined behavior.
+	const u64 seed = static_cast<s64>(pos.Y + (heat + humidity) * 0.9f);
 	PcgRandom rng(seed);
 
 	if (biome_closest_blend && dist_min_blend <= dist_min &&

src/nodedef.cpp

@@ -356,6 +356,8 @@ void ContentFeatures::reset()
 	has_on_construct = false;
 	has_on_destruct = false;
 	has_after_destruct = false;
+	floats = false;
+
 	/*
 		Actual data
 

src/tool.cpp

@@ -416,8 +416,7 @@ DigParams getDigParams(const ItemGroupList &groups,
 			// The actual number of uses increases
 			// exponentially with leveldiff.
 			// If the levels are equal, real_uses equals cap.uses.
-			u32 real_uses = cap.uses * pow(3.0, leveldiff);
-			real_uses = MYMIN(real_uses, U16_MAX);
+			const u32 real_uses = std::min<f64>(cap.uses * pow(3.0, leveldiff), U16_MAX);
 			result_wear = calculateResultWear(real_uses, initial_wear);
 			result_main_group = groupname;
 		}