strace: update to 4.21

[DrRamm]

Build log

make  all-am
make[3]: Entering directory '/build/strace-4.21/tests'
make[3]: Nothing to be done for 'all-am'.
make[3]: Leaving directory '/build/strace-4.21/tests'
make[2]: Leaving directory '/build/strace-4.21/tests'
make[1]: Leaving directory '/build/strace-4.21'
rm ioctlsort0.o ioctlsort0 ioctls_all0.h
+ arm-linux-musleabihf-strip strace
+ '[' -d /output ']'
++ uname
++ tr A-Z a-z
+ OUT_DIR=/output/linux/arm
+ mkdir -p /output/linux/arm
+ cp /build/strace-4.21/strace /output/linux/arm/
+ echo '** Finished **'
** Finished **

Tested on arm32

~ # ./cache/strace -V
strace -- version 4.21
Copyright (c) 1991-2018 The strace developers <https://strace.io>.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Optional features enabled: (none)