fixed unused variables warnings

Author: nnarain

src/core/apu.cpp

@@ -216,7 +216,7 @@ namespace gb
 		{
 			uint8_t value = 0;
 
-			auto extras = extra_bits_[addr - APU_REG_BASE];
+			const auto extras = extra_bits_[addr - APU_REG_BASE];
 
 			if (addr == memorymap::NR52_REGISTER)
 			{
@@ -251,7 +251,7 @@ namespace gb
 				}
 			}
 
-			return value;
+			return value | extras;
 		}
 
 		void write(uint8_t value, uint16_t addr)

src/core/cpu.cpp

@@ -2023,7 +2023,6 @@ namespace gb
 
 		void printDisassembly(uint8_t opcode, uint16_t userdata_addr, OpcodePage page)
 		{
-			const int spaces_before_registers = 13;
 			char str[32];
 
 			OpcodeInfo opcodeinfo = getOpcodeInfo(opcode, page);

src/core/tilemap.cpp

@@ -204,7 +204,6 @@ namespace gb
 		{
 			// make std::array?
 			std::vector<uint8_t> tiles;
-			auto idx = 0;
 
 			forEachBackgroundTile([&](uint8_t tile){
 				tiles.push_back(tile);
@@ -238,8 +237,6 @@ namespace gb
 
 			const auto start_tile_col = scx / tile_width;
 
-			std::size_t seed = 0;
-
 			for (auto line = 0; line < 144; line += 8)
 			{
 				const auto tile_row = ((scy + line) / tile_height);