vvfat: add a constant for bootsector name

Also add links to related compatibility problems.
Signed-off-by: NHervé Poussineau <hpoussin@reactos.org>
Reviewed-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

block/vvfat.c

@@ -71,6 +71,12 @@ void nonono(const char* file, int line, const char* msg) {
 
 #endif
 
+/* bootsector OEM name. see related compatibility problems at:
+ * https://jdebp.eu/FGA/volume-boot-block-oem-name-field.html
+ * http://seasip.info/Misc/oemid.html
+ */
+#define BOOTSECTOR_OEM_NAME "MSWIN4.1"
+
 #define DIR_DELETED 0xe5
 #define DIR_KANJI DIR_DELETED
 #define DIR_KANJI_FAKE 0x05
@@ -1028,7 +1034,7 @@ static int init_directories(BDRVVVFATState* s,
     bootsector->jump[0]=0xeb;
     bootsector->jump[1]=0x3e;
     bootsector->jump[2]=0x90;
-    memcpy(bootsector->name, "MSWIN4.1", 8);
+    memcpy(bootsector->name, BOOTSECTOR_OEM_NAME, 8);
     bootsector->sector_size=cpu_to_le16(0x200);
     bootsector->sectors_per_cluster=s->sectors_per_cluster;
     bootsector->reserved_sectors=cpu_to_le16(1);