Dependency from directories

Describe dependency upon directories
with '|' gmake feature.
reduce checks when create dirs
gcc should use -std=gnu++0x; CLang: turn on C++-11 mode

Use -std=gnu++0x on regular basis for gcc,
code is essential C++11 code now.

Add -std=gnu++0x for CLang, as for gcc.
Remove unusseful for CLang option

-nodefaultlibs unuseful for CLang.
Helper for debug make dependencies

Inspired by idea of John Graham-Cumming.

Define DEBUG_RULES to print target,
dependencies, that was origin of build target
and list of all dependenies.

If DEBUG_RULES is not 1, in addition it trace commands.
gcc: exact options, .spp, exact compiler

Don't prepend TARGET_OS prefix for exactly specified compilers
(via _FORCE_XXXXX).

If defined EXACT_OPTIONS don't use options as in 'normal' case.
Let's allow say what author want.

Add compile string for .spp (assembler with preprocessor) sources.