bugfix: Verify runtime/sake built correctly (3/n)

Author: jonahbeckford

src/r-c-ocaml-2-build_host.sh

@@ -171,7 +171,7 @@ fi
 export OCAMLSRC_MIXED
 
 # Until init_hostvars we can't use HOST_EXE_EXT
-if "${COMSPEC:-}"; then host_ext=.exe ; else host_ext=; fi
+if [ -n "${COMSPEC:-}" ]; then host_ext=.exe ; else host_ext=; fi
 
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