Move externs to header files

Follow Linux kernel coding style.

Remove exception from checkpatch.pl configuration file.

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

include/asm/asm.h

@@ -36,4 +36,6 @@ extern struct sSymbol *tHashedSymbols[HASHSIZE];
 extern struct sSymbol *pPCSymbol;
 extern bool oDontExpandStrings;
 
+size_t symvaluetostring(char *dest, size_t maxLength, char *sym);
+
 #endif /* RGBDS_ASM_ASM_H */

include/asm/fstack.h

@@ -41,6 +41,4 @@ void fstk_RunRept(uint32_t count);
 FILE *fstk_FindFile(char *fname);
 int32_t fstk_GetLine(void);
 
-extern int yywrap(void);
-
 #endif /* RGBDS_ASM_FSTACK_H */

include/asm/lexer.h

@@ -37,6 +37,8 @@ enum eLexerState {
 
 typedef struct yy_buffer_state *YY_BUFFER_STATE;
 
+void setup_lexer(void);
+
 void yy_set_state(enum eLexerState i);
 YY_BUFFER_STATE yy_create_buffer(FILE *f);
 YY_BUFFER_STATE yy_scan_bytes(char *mem, uint32_t size);
@@ -52,6 +54,7 @@ void lex_FloatDeleteSecondRange(uint32_t id, uint16_t start, uint16_t end);
 void lex_Init(void);
 void lex_AddStrings(const struct sLexInitString *lex);
 void lex_SetBuffer(char *buffer, uint32_t len);
+int yywrap(void);
 uint32_t yylex(void);
 void yyunput(char c);
 void yyunputstr(char *s);

include/asm/main.h

@@ -24,6 +24,8 @@ extern int32_t nBinaryID;
 extern struct sOptions DefaultOptions;
 extern struct sOptions CurrentOptions;
 
+extern FILE *dependfile;
+
 void opt_Push(void);
 void opt_Pop(void);
 void opt_Parse(char *s);

include/asm/output.h

@@ -18,6 +18,8 @@ struct Section {
 	uint8_t *tData;
 };
 
+extern char *tzObjectname;
+
 void out_PrepPass2(void);
 void out_SetFileName(char *s);
 void out_NewSection(char *pzName, uint32_t secttype);