corelib: Support ELFOSABI_LINUX in qelfparser

ELFOSABI_LINUX is the old name for ELFOSABI_GNU
and some systems (NetBSD 9) with an old elf.h
still use that define instead of ELFOSABI_GNU.

Pick-to: 6.4 6.4.1
Change-Id: I3d18efe117ea21f13831df5293b4efce99694294
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/plugin/qelfparser_p.cpp

@@ -20,6 +20,11 @@
 #  error "Need ELF header to parse plugins."
 #endif
 
+// Support older ELFOSABI define for GNU/Linux
+#if !defined(ELFOSABI_GNU) && defined(ELFOSABI_LINUX)
+#  define ELFOSABI_GNU ELFOSABI_LINUX
+#endif
+
 QT_BEGIN_NAMESPACE
 
 using namespace Qt::StringLiterals;