Use e_entry if "_start" can't be found on architectures where it is needed
diff --git a/ltrace.1 b/ltrace.1
index 5b73e37..75b0ea6 100644
--- a/ltrace.1
+++ b/ltrace.1
@@ -132,7 +132,8 @@
after the dynamic linker has run. If this flag is used, then the breakpoint
is set at
.IR extern ,
-which must be an external function. By default, 'main' is used.
+which must be an external function. By default, '_start' is used.
+NOTE: this flag is only available on the architectures that need it.
.TP
.I \-x extern
Trace the external function