Minix 3.3.0 fails as before (with decision not to fix).



One more failure on a not-so-common system:
I'm adding Alpine Linux to my test suite ( https://alpinelinux.org/ ).
Alpine is a lightweight Linux-based system, with musl libc and busybox utilities - so not very GNU-like, and possibly not POSIX compliant.
On this system, zdiff check fails because busybox's diff does not support the "-c" option
( https://busybox.net/downloads/BusyBox.html#diff ).
I suspect such systems will become more common in the future (due to usage in small VMs / containers).
 
Example:

    $ uname -a
    Linux alp333 4.1.20-0-grsec #1-Alpine SMP Mon Mar 21 15:49:51 GMT 2016 x86_64 Linux

    $ make check
    ...
    make[3]: Entering directory '/tmp/gzip-1.6.56-9190.CaiIeG/gzip-1.6.56-9190'
     GEN      check-local
    diff: unrecognized option: c
    [...]
    Makefile:2196: recipe for target 'check-local' failed
    make[3]: *** [check-local] Error 1
    make[3]: Leaving directory '/tmp/gzip-1.6.56-9190.CaiIeG/gzip-1.6.56-9190'
    Makefile:1985: recipe for target 'check-am' failed
    make[2]: *** [check-am] Error 2


    $ grep -A 5 check-local Makefile.am
    check-local: $(FILES_TO_CHECK) $(bin_PROGRAMS) gzip.doc.gz
        $(AM_V_GEN)$(new_path); { test '$(srcdir)' != . \
                                    || zdiff -c gzip.doc.gz; }
        $(AM_V_at)$(new_path); zdiff -c $(srcdir)/gzip.doc $(srcdir)/gzip.doc
        $(AM_V_at)$(new_path); zdiff $(srcdir)/gzip.doc gzip.doc.gz
        $(AM_V_at)$(new_path); zdiff -c - $(srcdir)/gzip.doc <gzip.doc.gz



    $ diff -c
    diff: unrecognized option: c
    BusyBox v1.24.1 (2015-12-16 08:00:02 GMT) multi-call binary.

    Usage: diff [-abBdiNqrTstw] [-L LABEL] [-S FILE] [-U LINES] FILE1 FILE2

    Compare files line by line and output the differences between them.
    This implementation supports unified diffs only.

        -a      Treat all files as text
        -b      Ignore changes in the amount of whitespace
        -B      Ignore changes whose lines are all blank
        -d      Try hard to find a smaller set of changes
        -i      Ignore case differences
        -L      Use LABEL instead of the filename in the unified header
        -N      Treat absent files as empty
        -q      Output only whether files differ
        -r      Recurse
        --no-dereference Don't follow symlinks
        -S      Start with FILE when comparing directories
        -T      Make tabs line up by prefixing a tab when necessary
        -s      Report when two files are the same
        -t      Expand tabs to spaces in output
        -U      Output LINES lines of context
        -w      Ignore all whitespace



regards,
 - assaf