This changes the buildlink3.mk files to use an include guard for the
recursive include. The use of BUILDLINK_DEPTH, BUILDLINK_DEPENDS,
BUILDLINK_PACKAGES and BUILDLINK_ORDER is handled by a single new
variable BUILDLINK_TREE. Each buildlink3.mk file adds a pair of
enter/exit marker, which can be used to reconstruct the tree and
to determine first level includes. Avoiding := for large variables
(BUILDLINK_ORDER) speeds up parse time as += has linear complexity.
The include guard reduces system time by avoiding reading files over and
over again. For complex packages this reduces both %user and %sys time to
half of the former time.
fixed: corrupt floating-point audio on big-endian machines
fixed: limit RIFF data buffering to 16 MB to prevent out-of-memory crash
improved: attempt to mute errors when decoding corrupt legacy WavPack files
improved: overall performance enhancements of 10% to 30% (depending on mode)
added: MMX intrinsics for 24-bit (and higher) stereo encoding (thanks to
Joachim Henke)
added: --skip and --until commands to unpack specified range of audio data
