auto_rx/build.sh: exit immediatelly on error

This ensures script will not continue to build when error accures. Continuing the build
after some part fails only brings more errors and makes the output harder to understand.

auto_rx/build.sh

@@ -2,6 +2,8 @@
 #
 # Auto Sonde Decoder build script.
 
+set -e
+
 # Get the auto-rx version.
 AUTO_RX_VERSION="\"$(python3 -m autorx.version 2>/dev/null || python -m autorx.version)\""