diff --git a/lib/ChangeLog b/lib/ChangeLog
index a6f3ca4..13426ee 100644
--- a/lib/ChangeLog
+++ b/lib/ChangeLog
@@ -1,5 +1,9 @@
 2005-04-08 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
 
+	* sigevent.c: On GNU_LINUX, check whether __USE_GNU is already defined.
+
+2005-04-08 Andrew J. Schorr <ajschorr@alumni.princeton.edu>
+
 	* vty.c: (vty_log_fixed) Use casts to (void *) to try to eliminate
 	  compiler warnings when assigning a (const char *) value to
 	  struct iovec iov_base.
diff --git a/lib/sigevent.c b/lib/sigevent.c
index 9c25d76..08141af 100644
--- a/lib/sigevent.c
+++ b/lib/sigevent.c
@@ -27,7 +27,9 @@
 #ifdef HAVE_UCONTEXT_H
 #ifdef GNU_LINUX
 /* get REG_EIP from ucontext.h */
+#ifndef __USE_GNU
 #define __USE_GNU
+#endif /* __USE_GNU */
 #endif /* GNU_LINUX */
 #include <ucontext.h>
 #endif /* HAVE_UCONTEXT_H */