ext/exif: spell the Exif identifier code as a char literal

The {0x45, 0x78, 0x69, 0x66, 0x00, 0x00} arrays are the ASCII bytes for
"Exif\0\0"; the char form is byte-identical and self-documenting.

Author: iliaal

ext/exif/exif.c

@@ -3750,7 +3750,7 @@ static void exif_process_TIFF_in_JPEG(image_info_type *ImageInfo, char *CharBuf,
 static void exif_process_APP1(image_info_type *ImageInfo, char *CharBuf, size_t length, size_t displacement)
 {
 	/* Check the APP1 for Exif Identifier Code */
-	static const uchar ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
+	static const uchar ExifHeader[] = {'E', 'x', 'i', 'f', 0, 0};
 	if (length <= 8 || memcmp(CharBuf+2, ExifHeader, 6)) {
 		exif_error_docref(NULL EXIFERR_CC, ImageInfo, E_WARNING, "Incorrect APP1 Exif Identifier Code");
 		return;
@@ -4447,8 +4447,7 @@ static bool exif_scan_HEIF_header(image_info_type *ImageInfo, unsigned char *buf
 
 static bool exif_scan_WEBP_header(image_info_type *ImageInfo, size_t riff_size)
 {
-	/* "Exif\0\0" identifier code */
-	static const uchar ExifHeader[] = {0x45, 0x78, 0x69, 0x66, 0x00, 0x00};
+	static const uchar ExifHeader[] = {'E', 'x', 'i', 'f', 0, 0};
 	unsigned char chunk_header[8];
 	size_t offset = 12;
 	size_t riff_end = riff_size <= ImageInfo->FileSize - 8 ? riff_size + 8 : ImageInfo->FileSize;