9882d1f044133832b3c0809676d5f26a861b9f44 Reset default -g -O2 flags when enable debug (Chun Kuan Lee)
Pull request description:
The default CXXFLAGS is -g -O2, this should not appear when enable debug. fixes #13432
Tree-SHA512: 79447f3e1fab9e6cd12f5ca49b3d42187e856e0c159ed01140ea93d6ef1fbb1af3d65b338308566330491052c0177d12abe26796513502ddde31692665a0dbb4
This is a port of core PR #13445