Cleanup code of rgbfix, rgbgfx and external libs

Follow Linux kernel coding style.

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

include/extern/err.h

@@ -2,10 +2,13 @@
 #define EXTERN_ERR_H
 
 #ifdef ERR_IN_LIBC
+
 #include <err.h>
-#else
+
+#else /* ERR_IN_LIBC */
 
 #include <stdarg.h>
+
 #include "extern/stdnoreturn.h"
 
 #define warn rgbds_warn
@@ -18,16 +21,16 @@
 #define errx rgbds_errx
 #define verrx rgbds_verrx
 
-void warn(const char *, ...);
-void vwarn(const char *, va_list);
-void warnx(const char *, ...);
-void vwarnx(const char *, va_list);
+void warn(const char *fmt, ...);
+void vwarn(const char *fmt, va_list ap);
+void warnx(const char *fmt, ...);
+void vwarnx(const char *fmt, va_list ap);
 
-noreturn void err(int, const char *, ...);
-noreturn void verr(int, const char *, va_list);
-noreturn void errx(int, const char *, ...);
-noreturn void verrx(int, const char *, va_list);
+noreturn void err(int status, const char *fmt, ...);
+noreturn void verr(int status, const char *fmt, va_list ap);
+noreturn void errx(int status, const char *fmt, ...);
+noreturn void verrx(int status, const char *fmt, va_list ap);
 
-#endif
+#endif /* ERR_IN_LIBC */
 
-#endif
+#endif /* EXTERN_ERR_H */

include/extern/reallocarray.h

@@ -2,13 +2,14 @@
 #define EXTERN_REALLOCARRAY_H
 
 #ifdef REALLOCARRAY_IN_LIBC
+
 #include <stdlib.h>
-#else
+
+#else /* REALLOCARRAY_IN_LIBC */
 
 #define reallocarray rgbds_reallocarray
-
 void *reallocarray(void *, size_t, size_t);
 
-#endif
+#endif /* REALLOCARRAY_IN_LIBC */
 
-#endif
+#endif /* EXTERN_REALLOCARRAY_H */

include/extern/stdnoreturn.h

@@ -1,16 +1,21 @@
+#ifndef EXTERN_STDNORETURN_H
+#define EXTERN_STDNORETURN_H
+
 #if __STDC_VERSION__ >= 201112L
-    /* C11 or newer */
-    #define noreturn _Noreturn
+	/* C11 or newer */
+	#define noreturn _Noreturn
 #elif __cplusplus >= 201103L
-    /* C++11 or newer */
-    #define noreturn [[noreturn]]
+	/* C++11 or newer */
+	#define noreturn [[noreturn]]
 #elif __GNUC__ > 2 || (__GNUC__ == 2 && (__GNUC_MINOR__ >= 5))
-    /* GCC 2.5 or newer */
-    #define noreturn __attribute__ ((noreturn))
+	/* GCC 2.5 or newer */
+	#define noreturn __attribute__ ((noreturn))
 #elif _MSC_VER >= 1310
-    /* MS Visual Studio 2003/.NET Framework 1.1 or newer */
-    #define noreturn _declspec( noreturn)
+	/* MS Visual Studio 2003/.NET Framework 1.1 or newer */
+	#define noreturn _declspec(noreturn)
 #else
-    /* unsupported, but no need to throw a fit */
-    #define noreturn
+	/* Unsupported, but no need to throw a fit */
+	#define noreturn
 #endif
+
+#endif /* EXTERN_STDNORETURN_H */

include/extern/strl.h

@@ -1,13 +1,17 @@
-#ifndef STRL_H
-#define STRL_H
+#ifndef EXTERN_STRL_H
+#define EXTERN_STRL_H
 
 #ifdef STRL_IN_LIBC
+
 #include <string.h>
-#else
+
+#else /* STRL_IN_LIBC */
+
 #define strlcpy rgbds_strlcpy
 #define strlcat rgbds_strlcat
-size_t strlcpy(char *, const char *, size_t);
-size_t strlcat(char *, const char *, size_t);
-#endif
+size_t strlcpy(char *dst, const char *src, size_t dsize);
+size_t strlcat(char *dst, const char *src, size_t dsize);
 
-#endif
+#endif /* STRL_IN_LIBC */
+
+#endif /* EXTERN_STRL_H */

include/extern/version.h

@@ -14,8 +14,13 @@
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
+#ifndef EXTERN_VERSION_H
+#define EXTERN_VERSION_H
+
 #define PACKAGE_VERSION_MAJOR (0)
 #define PACKAGE_VERSION_MINOR (3)
 #define PACKAGE_VERSION_PATCH (3)
 
-const char * get_package_version_string(void);
+const char *get_package_version_string(void);
+
+#endif /* EXTERN_VERSION_H */

include/gfx/gb.h

@@ -20,11 +20,14 @@
 #include <stdint.h>
 #include "gfx/main.h"
 
-void png_to_gb(struct PNGImage png, struct GBImage *gb);
-void output_file(struct Options opts, struct GBImage gb);
-int get_tile_index(uint8_t *tile, uint8_t **tiles, int num_tiles, int tile_size);
-void create_tilemap(struct Options opts, struct GBImage *gb, struct Tilemap *tilemap);
-void output_tilemap_file(struct Options opts, struct Tilemap tilemap);
-void output_palette_file(struct Options opts, struct PNGImage png);
+void png_to_gb(const struct PNGImage png, struct GBImage *gb);
+void output_file(const struct Options opts, const struct GBImage gb);
+int get_tile_index(uint8_t *tile, uint8_t **tiles, int num_tiles,
+		   int tile_size);
+void create_tilemap(const struct Options opts, struct GBImage *gb,
+		    struct Tilemap *tilemap);
+void output_tilemap_file(const struct Options opts,
+			 const struct Tilemap tilemap);
+void output_palette_file(const struct Options opts, const struct PNGImage png);
 
 #endif

include/gfx/main.h

@@ -72,4 +72,4 @@ int depth, colors;
 #include "gfx/makepng.h"
 #include "gfx/gb.h"
 
-#endif
+#endif /* RGBDS_GFX_MAIN_H */

include/gfx/makepng.h

@@ -19,10 +19,10 @@
 
 #include "gfx/main.h"
 
-void input_png_file(struct Options opts, struct PNGImage *img);
+void input_png_file(const struct Options opts, struct PNGImage *img);
 void get_text(struct PNGImage *png);
-void set_text(struct PNGImage *png);
-void output_png_file(struct Options opts, struct PNGImage *png);
-void free_png_data(struct PNGImage *png);
+void set_text(const struct PNGImage *png);
+void output_png_file(const struct Options opts, const struct PNGImage *png);
+void free_png_data(const struct PNGImage *png);
 
-#endif
+#endif /* RGBDS_GFX_PNG_H */