Fixed compiling of ztest: setting the path to static zdb was missing a macro expansion.

cherry-picked from 600109f
Re-added libzpool, zdb and ztest.

cherry-picked from 55d18b1
Fixed compilation with clang-3.5 compiler.
Changed build rule set to support a "VERBOSE=" and a "LD=" make variable.
If "VERBOSE" is not given, then suppress most output and only write one-liner
"Compiling / Creating / Linking ..." messages.
The "LD" variable allows to specify an alternative linker.

Also slightly enhanced help output and fixed a quoting error in the flags-* targets.
Fixed "Crash on symlink" bug.

Problems was, that the symlink callback did not returned the vnode of the
created link to VFS.  Upto Mountain Lion this was a "should", in Mavericks
it is a "must" requirement.

(fixes issue 120)
Implemented new support target which runs dsymutil.
Created new helper scripts to simplify remote kernel debugging.
Fixed search for panic reports, failed to find anything due to dublicated path prefix.

Patch suggested by "andy@aligature.com" via bug tracker.
Fixed handling of LD variable, which was not getting its proper default value.