scripts: refine static linking check to better guide the user

The current mechanism to check if static linking is possible, and the mesage
displayed on failure, can be puzzling to the unsuspecting user.

Also, the current implementation is not using the existing infrastructure,
and is thus difficult to enhance with new tests.

So, switch to using the standard CT_DoExecLog infra, and use four tests to
check for the host compiler:
- check we can run it
- check it can build a trivial program
- check it can statically link that program
- check if it statically link with libstdc++

That should cover most of the problems. Hopefully.

(At the same time, fix a typo in a comment)

Signed-off-by: Daniel Price <daniel.price@gmail.com>
[yann.morin.1998@free.fr: split original patch for self-contained changes]
[yann.morin.1998@free.fr: use steps to better see gcc's output]
[yann.morin.1998@free.fr: commit log]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <163f86b5216fc08c672a.1353459722@nipigon.dssd.com>
Patchwork-Id: 200536

 # Kernel options

 menu "Operating System"

 # Config option used throughout the config and code to determine wether

 # we have a kernel or not (there might be different bare metal stuff)...

 config BARE_METAL

     bool

 config WINDOWS

     bool

 # Each target OS (aka kernel) that support shared libraries can select

 # this, so the user can decide whether or not to build a shared library

 # enabled toolchain

 config KERNEL_SUPPORTS_SHARED_LIBS

     bool

 config KERNEL

     string

 config KERNEL_VERSION

     string

 source "config.gen/kernel.in"

 comment "Common kernel options"

 config SHARED_LIBS

     bool

     prompt "Build shared libraries"

     depends on KERNEL_SUPPORTS_SHARED_LIBS

     default y

     help

       Say 'y' here, unless you don't want shared libraries.

       You might not want shared libraries if you're building for a target that

       don't support it (maybe some nommu targets, for example, or bare metal).

 source "config.gen/kernel.in.2"

 endmenu