bshell: re-organise build into three separate components

bshell: the front-end binary
bshell.runtime: contains the parser, compiler, and classes needed to run bshell scripts
bshell.core: contains the builtin commandlets and aliases

bshell.runtime/status.c

@@ -0,0 +1,19 @@
+#include <bshell/status.h>
+#include <errno.h>
+
+enum bshell_status bshell_status_from_errno(int err)
+{
+	switch (err) {
+	case 0:
+		return BSHELL_SUCCESS;
+	case EIO:
+		return BSHELL_ERR_IO_FAILURE;
+	case ENOENT:
+		return BSHELL_ERR_NO_ENTRY;
+	case EPERM:
+	case EACCES:
+		return BSHELL_ERR_ACCESS_DENIED;
+	default:
+		return BSHELL_ERR_INTERNAL_FAILURE;
+	}
+}