memory corruption on startup caused by 5219c37f7c98f37f078fee00fe8ca35d83ff4f5d

commit 5219c37f7c98f37f078fee00fe8ca35d83ff4f5d
Author: Thiago Macieira <thiago.macieira@intel.com>
Date:   Wed Jun 20 15:20:32 2018 -0700

    QLibrary: find AVX2 (Haswell) optimized plugins and libraries
    
    Libraries are placed in a subdir "haswell/" of the main library dir,
    whereas plugins are simply named with ".avx2" appended to the plugin
    name (plugin.so.avx2). The "haswell/" library directory suffix is a
    convention found in glibc since version 2.26, whereas the ".avx2" and
    ".avx512" suffixes are a convention found in the Clear Linux OS for
    Intel Architecture.
    
    This patch implements this for all Unix OSes, except for Darwin, where
    the fat file format already has a sub-architecture for Haswell
    (x86_64h).
    
    We could also implement the "sse2/" subdir search for libraries, but I
    don't think it's worth the cost in 2018.
    
    Change-Id: Iff4151c519c144d580c4fffd1539fe5ee9a4d7b1
    Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
    Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>