diff --git a/man3/abs.3 b/man3/abs.3
index 7016fc226..da2570b30 100644
--- a/man3/abs.3
+++ b/man3/abs.3
@@ -121,6 +121,7 @@ to be declared, it may be necessary to define
 \fB_ISOC99_SOURCE\fP or \fB_ISOC9X_SOURCE\fP (depending on the
 version of glibc) before including any standard headers.
 .PP
+By default,
 GCC handles
 .BR abs (),
 .BR labs (),