Make sure compiler install scripts are executable

miosix/_tools/compiler/gcc-9.2.0-mp3.2/cleanup.sh

miosix/_tools/compiler/gcc-9.2.0-mp3.2/download.sh

miosix/_tools/compiler/gcc-9.2.0-mp3.2/install-script.sh

...ompiler/gcc-9.2.0-mp3.2/installers/additional-download.sh

.../compiler/gcc-9.2.0-mp3.2/installers/checkdeps-windows.sh

...x/_tools/compiler/gcc-9.2.0-mp3.2/installers/checkdeps.sh

...9.2.0-mp3.2/installers/macos/ScriptsTemplates/postinstall

miosix/_tools/compiler/gcc-9.2.0-mp3.2/ramdisk.sh

miosix/_tools/compiler/gcc-9.2.0-mp3.2/uninstall.sh