Tested compiler detection with the QNX 7.0 list of compiler targets:
* gcc_ntoaarch64le
* gcc_ntoaarch64le_cxx
* gcc_ntoarmv7le
* gcc_ntoarmv7le_cxx
* gcc_ntox86_cxx
* gcc_ntoaarch64le_gpp
* gcc_ntox86_64_gpp
* gcc_ntoarmv7le_gpp
* gcc_ntox86_64_cxx
* gcc_ntox86
* gcc_ntox86_gpp
* gcc_ntox86_64
This commit fixes some of the problems described in:
https://cristianadam.eu/20181202/a-better-qnx-cmake-toolchain-file/
