sanity-check-depends (was: Patterns like >=x.*)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> +_SANITY_CHECK_DEPENDS_CMD=${AWK} '        \
I didn't look at the details, but maybe it's cheaper to do something like
        if !empty(${DEPENDS:C/<pattern matching valid dependencies>//})
?

> +     @{ ${DEPENDS:@temp@echo '${temp}';@} \
1. The man pages states that the convention is to have the loop variable 
start and end with a period.

2. What am I overlooking that
        printf "%s\n" ${DEPENDS} ${BUILD_DEPENDS} ${TOOL_DEPENDS} ${CONFLICTS}
doesn't work?