diff --git a/ports/esp8266/Makefile b/ports/esp8266/Makefile
index 9a7476c102..989e8a62f3 100644
--- a/ports/esp8266/Makefile
+++ b/ports/esp8266/Makefile
@@ -138,6 +138,7 @@ LIB_SRC_C = $(addprefix lib/,\
 	libm/asinfacosf.c \
 	libm/atanf.c \
 	libm/atan2f.c \
+	libm/roundf.c \
 	mp-readline/readline.c \
 	netutils/netutils.c \
 	timeutils/timeutils.c \
diff --git a/ports/nrf/Makefile b/ports/nrf/Makefile
index 04e3b7fee0..d898559a18 100644
--- a/ports/nrf/Makefile
+++ b/ports/nrf/Makefile
@@ -150,6 +150,7 @@ SRC_LIB += $(addprefix lib/,\
         libm/asinfacosf.c \
         libm/atanf.c \
         libm/atan2f.c \
+        libm/roundf.c \
 	)
 
 endif
diff --git a/ports/qemu-arm/Makefile b/ports/qemu-arm/Makefile
index cb7dcb0216..b31284c59b 100644
--- a/ports/qemu-arm/Makefile
+++ b/ports/qemu-arm/Makefile
@@ -90,6 +90,7 @@ LIB_SRC_C += $(addprefix lib/,\
 	libm/asinfacosf.c \
 	libm/atanf.c \
 	libm/atan2f.c \
+	libm/roundf.c \
 	utils/sys_stdio_mphal.c \
 	)
 
diff --git a/ports/stm32/Makefile b/ports/stm32/Makefile
index 2dc7405618..31d75f3fbe 100644
--- a/ports/stm32/Makefile
+++ b/ports/stm32/Makefile
@@ -214,6 +214,7 @@ SRC_LIBM = $(addprefix lib/libm/,\
 	kf_tan.c \
 	log1pf.c \
 	nearbyintf.c \
+	roundf.c \
 	sf_cos.c \
 	sf_erf.c \
 	sf_frexp.c \