uclibc++: make verbosity affect uClibc++ build

uclibc++: make verbosity affect uClibc++ build

Before this change, setting the verbosity to anything with V=blah would
cause uclibc++ build to print errors to the screen. Now, it the
clibc++ build verbosity will be altered in the following manners:
* V=s will set V=1 in the uclibc++ build
* V=sc will set V=2 in the uclibc++ build

Signed-off-by: Wren Turkal <wt@penguintechs.org>