[FREELDR][BTRFS] Implemented BTRFS support in Free Loader. Now it sup…

…ports case-insensitive path lookup, symlink folowing and reading uncompressed files.

Volume boot record is also implemented, it supports reading BTRFS tree structures with upto 64k node size.
This support required to change all path in Free Loader to lowercase for better performance.
CORE-13769

boot/freeldr/bootsect/CMakeLists.txt

@@ -6,6 +6,7 @@ if(ARCH STREQUAL "i386" OR ARCH STREQUAL "amd64")
 
     CreateBootSectorTarget(fat ${CMAKE_CURRENT_SOURCE_DIR}/fat.S ${CMAKE_CURRENT_BINARY_DIR}/fat.bin 7c00)
     CreateBootSectorTarget(fat32 ${CMAKE_CURRENT_SOURCE_DIR}/fat32.S ${CMAKE_CURRENT_BINARY_DIR}/fat32.bin 7c00)
+    CreateBootSectorTarget(btrfsvbr ${CMAKE_CURRENT_SOURCE_DIR}/btrfs.S ${CMAKE_CURRENT_BINARY_DIR}/btrfs.bin 7c00)
 
     ## New versions using FATY.S (experimental)
     # add_definitions(-DFAT12)
@@ -24,6 +25,7 @@ if(ARCH STREQUAL "i386" OR ARCH STREQUAL "amd64")
 
     add_cd_file(TARGET dosmbr DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/dosmbr.bin FOR bootcd regtest)
     add_cd_file(TARGET ext2 DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/ext2.bin FOR bootcd regtest)
+    add_cd_file(TARGET btrfsvbr DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/btrfs.bin FOR bootcd regtest)
     add_cd_file(TARGET fat DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/fat.bin FOR bootcd regtest)
     add_cd_file(TARGET fat32 DESTINATION loader NO_CAB FILE ${CMAKE_CURRENT_BINARY_DIR}/fat32.bin FOR bootcd regtest)
     add_cd_file(TARGET isoboot DESTINATION loader NO_CAB NOT_IN_HYBRIDCD FILE ${CMAKE_CURRENT_BINARY_DIR}/isoboot.bin FOR all hybridcd)