and clear error on first successful build

In file included from /usr/include/pthread.h:30:0,
                 from src/OpenSceneGraph-3.4.0/src/OpenThreads/pthreads/PThread.cpp:23:
src/OpenSceneGraph-3.4.0/src/OpenThreads/pthreads/PThread.cpp: In static member function 'static void* OpenThreads::ThreadPrivateActions::StartThread(void*)':
src/OpenSceneGraph-3.4.0/src/OpenThreads/pthreads/PThread.cpp:140:13: error: 'memset' was not declared in this scope
             CPU_ZERO( &cpumask );

Disable check()

PHP7 appears to be supported since release 2.2.0
https://github.com/Icinga/icingaweb2/issues/2027

There's some problem with that package and it seems that it just needs
to be rebuilt.

Currently this package FTBFS on ppc64le due to old config.guess, which
causes:

	checking build system type... ./config.guess: unable to guess system type

This commit just update it before running configure.

Musl lacks a.out.h header, since x86-64 kernel has this file. We do not
have this file, since glib usually have. Once we are on Musl, we lack
this file on non x86-64.

This patch simply switch to the project file definitions instead of
kernel/libc.

Disabling the blender build on ppc64le due to the following issue:

 pragma message "We don't know how to use malloc_usable_size on your platform"

Once we understand what is missing, it should be enabled.