config: avoid calling `labs()` on too-large data type

diff --git a/trace2/tr2_dst.h b/trace2/tr2_dst.h
index 9a64f05b0299df2444f7a1d93ccac77a713e40c2..3adf3bac139b1aa910b4aea0dc71e3b03ce722ed 100644 (file)
--- a/trace2/tr2_dst.h
+++ b/trace2/tr2_dst.h
@@ -2,9 +2,10 @@
 #define TR2_DST_H
 
 struct strbuf;
+#include "trace2/tr2_sysenv.h"
 
 struct tr2_dst {
-       const char *const env_var_name;
+       enum tr2_sysenv_variable sysenv_var;
        int fd;
        unsigned int initialized : 1;
        unsigned int need_close : 1;