Fix some warnings

Makefile

@@ -52,8 +52,8 @@ SOURCES_CPP	:= $(shell find -L $(SOURCEDIRS) -name "*.cpp")
 # Compiler and linker flags
 # -------------------------
 
-WARNFLAGS_C	:= -Wall -Wno-multichar -Wno-unused-but-set-variable \
-		   -Wno-unused-variable -Wno-unused-result
+WARNFLAGS_C	:= -Wall -Wextra -Wno-multichar -Wno-unused-but-set-variable \
+		   -Wno-unused-result -Wno-sign-compare -Wno-type-limits
 
 WARNFLAGS_CXX	:= -Wall
 

source/msl.c

@@ -70,7 +70,6 @@ void MSL_Erase( void )
 u16 MSL_AddSample( Sample* samp )
 {
 	u32 sample_length;
-	u32 x;
 	file_open_write_end( TMP_SAMP );
 
 	sample_length = samp->sample_length;
@@ -393,4 +392,4 @@ int MSL_Create( char* argv[], int argc, char* output, char* header, bool verbose
 	file_delete( TMP_SAMP );
 	file_delete( TMP_SONG );
 	return ERR_NONE;
-}
+}

source/s3m.c

@@ -269,8 +269,10 @@ int Load_S3M( MAS_Module* mod, bool verbose )
 	for( x = 0; x < 28; x++ )
 		mod->title[x] = read8();	// read song name
 
-	if( read8() != 0x1A );
+    read8(); // No need to check this value
+//	if( read8() != 0x1A )
 //		return ERR_INVALID_MODULE;
+
 	if( read8() != 16 )
 		return ERR_INVALID_MODULE;
 	if( verbose )

source/upload.c

@@ -24,5 +24,6 @@
 
 void Upload_GBA( char* filename )
 {
+	(void)filename;
 	// todo.........
 }