diff --git a/src/system/libroot/posix/math/Jamfile b/src/system/libroot/posix/math/Jamfile
index 7902285d5a..af51d59ad0 100644
--- a/src/system/libroot/posix/math/Jamfile
+++ b/src/system/libroot/posix/math/Jamfile
@@ -10,7 +10,7 @@ MergeObject posix_math.o :
 	acosh.c
 	asincos.c
 	asinh.c
-#	atan.c
+	atan.c
 	atanh.c
 	cabs.c
 	cbrt.c