If a user accidentally passes 'CMAKE_OSX_ARCHITECTURES=x86_64;arm64'
to configure on a Linux x86_64 platform, the build would fail when
compiling qdrawhelper_avx2.cpp.o either due to an architecture
mismatch, or due to not recognizing the -Xarch flag on older gcc
compilers.
Only add xarch flags to SIMD compilation on Apple platforms.
Change-Id: I322316979626b04cb0378f4dbf3cc26ec96183ac
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>
(cherry picked from commit 3f3d8604e6ed5b6854301f4a3c4799cfa256d8b0)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>