diff --git a/man3/alloca.3 b/man3/alloca.3
index a9f3f6515..c13d045bf 100644
--- a/man3/alloca.3
+++ b/man3/alloca.3
@@ -77,10 +77,12 @@ By default the glibc version of
 .I <stdlib.h>
 includes
 .I <alloca.h>
-and that contains the line
-.RS
-# define alloca(size)   __builtin_alloca (size)
-.RE
+and that contains the line:
+.nf
+
+    # define alloca(size)   __builtin_alloca (size)
+
+.fi
 with messy consequences if one has a private version of this function.
 .LP
 The fact that the code is inlined, means that it is impossible