ash: [BUILTIN] Merge SKIPFUNC/SKIPFILE and only clear SKIPFUNC when leaving dotcmd

ash: [BUILTIN] Merge SKIPFUNC/SKIPFILE and only clear SKIPFUNC when leaving dotcmd

Upstream commit:

    Date: Sat, 9 Jul 2011 22:05:22 +0800
    [BUILTIN] Merge SKIPFUNC/SKIPFILE and only clear SKIPFUNC when leaving dotcmd

    Currently upon leaving a dotcmd the evalskip state is reset so
    if a continue/break statement is used within a dot script it would
    have no effect outside of the dot script.

    This is inconsistent with other shells.

    This patch is based on one by Jilles Tjoelker and only clears
    SKIPFUNC when leaving a dot script.  As a result continue/break
    will remain in effect.

    It also merges SKIPFUNC/SKIPFILE as they have no practical difference.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>