subsys/cpp: make libstdc++ select full libc to get tests working

Using a STD C++ library requires a toolchain-provided C library with
associated STD C++ library. Instead of using a dependency on !MINIMAL_LIBC,
select REQUIRES_FULL_LIBC so that the build will select a viable C library
rather than failing.

This allows all of the C++ tests to be run as a part of a standard twister
run. I expect this will uncover regressions in some of those which haven't
been run recently.

Signed-off-by: Keith Packard <[email protected]>

Author: keith-packard

subsys/cpp/Kconfig

@@ -67,7 +67,7 @@ config CPP_MAIN
 
 config LIB_CPLUSPLUS
 	bool "Link with STD C++ library"
-	depends on !MINIMAL_LIBC
+	select REQUIRES_FULL_LIBC
 	help
 	  Link with STD C++ Library.