partclone v0.3.21

• Change C99 for loop init to C89 for compatibility
• Update autotools build files
• Avoid redefining _GNU_SOURCE, _LARGEFILE64_SOURCE
• Support FUSE 2.x API
• Check argument count in partclone.imgfuse
• Support out-of-tree builds for BTRFS and XFS
• Avoid uninitialized variables to prevent compiler warnings
• Check for EVP_MD_CTX_reset
• Remove unused variables to silence compiler warnings
• Detect FUSE version and explicitly print “yes” or “no” regarding filesystem support
• Fix MBR builds for x86, non-x86 and out-of-tree
• Support unit-testing in out-of-tree builds
• Fix typos