err: avoid defining progname if OS provides setprogname

diff --git a/usual/err.c b/usual/err.c
index 145c4c055d60e58d1de307e580a4a6cdea4d624d..c2a3a8beb47886b48939b15cb15d2494d90d67c0 100644 (file)
--- a/usual/err.c
+++ b/usual/err.c
@@ -24,7 +24,9 @@
 
 #include <usual/string.h>
 
+#ifndef HAVE_SETPROGNAME
 static const char *progname;
+#endif
 
 #ifndef HAVE_ERR
 void err(int e, const char *fmt, ...)