diff --git a/include/libopencm3/cm3/common.h b/include/libopencm3/cm3/common.h
index 8cd5b9b5..4aa879ce 100644
--- a/include/libopencm3/cm3/common.h
+++ b/include/libopencm3/cm3/common.h
@@ -86,7 +86,4 @@
 #define BIT30 (1<<30)
 #define BIT31 (1<<31)
 
-#define __packed __attribute__((packed))
-#define __aligned(x) __attribute__((aligned(x)))
-
 #endif
diff --git a/include/libopencm3/cm3/scb.h b/include/libopencm3/cm3/scb.h
index 024a8e17..9f043c3d 100644
--- a/include/libopencm3/cm3/scb.h
+++ b/include/libopencm3/cm3/scb.h
@@ -375,7 +375,7 @@ struct scb_exception_stack_frame {
 	uint32_t lr;
 	uint32_t pc;
 	uint32_t xpsr;
-} __packed;
+} __attribute__((packed));
 
 #define SCB_GET_EXCEPTION_STACK_FRAME(f)				\
 	do {								\
diff --git a/include/libopencm3/usb/cdc.h b/include/libopencm3/usb/cdc.h
index 3fd7ab39..3f0db919 100644
--- a/include/libopencm3/usb/cdc.h
+++ b/include/libopencm3/usb/cdc.h
@@ -88,7 +88,7 @@ struct usb_cdc_union_descriptor {
 	uint8_t bControlInterface;
 	uint8_t bSubordinateInterface0;
 	/* ... */
-} __packed;
+} __attribute__((packed));
 
 
 /* Definitions for Abstract Control Model devices from:
@@ -103,7 +103,7 @@ struct usb_cdc_call_management_descriptor {
 	uint8_t bDescriptorSubtype;
 	uint8_t bmCapabilities;
 	uint8_t bDataInterface;
-} __packed;
+} __attribute__((packed));
 
 /* Table 4: Abstract Control Management Functional Descriptor */
 struct usb_cdc_acm_descriptor {
@@ -111,7 +111,7 @@ struct usb_cdc_acm_descriptor {
 	uint8_t bDescriptorType;
 	uint8_t bDescriptorSubtype;
 	uint8_t bmCapabilities;
-} __packed;
+} __attribute__((packed));
 
 /* Table 13: Class-Specific Request Codes for PSTN subclasses */
 /* ... */
@@ -126,7 +126,7 @@ struct usb_cdc_line_coding {
 	uint8_t bCharFormat;
 	uint8_t bParityType;
 	uint8_t bDataBits;
-} __packed;
+} __attribute__((packed));
 
 /* Table 30: Class-Specific Notification Codes for PSTN subclasses */
 /* ... */
@@ -140,7 +140,7 @@ struct usb_cdc_notification {
 	uint16_t wValue;
 	uint16_t wIndex;
 	uint16_t wLength;
-} __packed;
+} __attribute__((packed));
 
 #endif
 
diff --git a/include/libopencm3/usb/dfu.h b/include/libopencm3/usb/dfu.h
index 0ebbffb3..b7f028c0 100644
--- a/include/libopencm3/usb/dfu.h
+++ b/include/libopencm3/usb/dfu.h
@@ -94,7 +94,7 @@ struct usb_dfu_descriptor {
 	uint16_t wDetachTimeout;
 	uint16_t wTransferSize;
 	uint16_t bcdDFUVersion;
-} __packed;
+} __attribute__((packed));
 
 #endif
 
diff --git a/include/libopencm3/usb/hid.h b/include/libopencm3/usb/hid.h
index da19b4de..87f4924d 100644
--- a/include/libopencm3/usb/hid.h
+++ b/include/libopencm3/usb/hid.h
@@ -51,7 +51,7 @@ struct usb_hid_descriptor {
 	uint16_t bcdHID;
 	uint8_t bCountryCode;
 	uint8_t bNumDescriptors;
-} __packed;
+} __attribute__((packed));
 
 #endif
 
diff --git a/include/libopencm3/usb/usbstd.h b/include/libopencm3/usb/usbstd.h
index 57fda341..f85ec82d 100644
--- a/include/libopencm3/usb/usbstd.h
+++ b/include/libopencm3/usb/usbstd.h
@@ -59,7 +59,7 @@ struct usb_setup_data {
 	uint16_t wValue;
 	uint16_t wIndex;
 	uint16_t wLength;
-} __packed;
+} __attribute__((packed));
 
 /* Class Definition */
 #define USB_CLASS_VENDOR			0xFF
@@ -131,7 +131,7 @@ struct usb_device_descriptor {
 	uint8_t iProduct;
 	uint8_t iSerialNumber;
 	uint8_t bNumConfigurations;
-} __packed;
+} __attribute__((packed));
 
 #define USB_DT_DEVICE_SIZE sizeof(struct usb_device_descriptor)
 
@@ -148,7 +148,7 @@ struct usb_device_qualifier_descriptor {
 	uint8_t bMaxPacketSize0;
 	uint8_t bNumConfigurations;
 	uint8_t bReserved;
-} __packed;
+} __attribute__((packed));
 
 /* USB Standard Configuration Descriptor - Table 9-10 */
 struct usb_config_descriptor {
@@ -167,7 +167,7 @@ struct usb_config_descriptor {
 		const struct usb_iface_assoc_descriptor *iface_assoc;
 		const struct usb_interface_descriptor *altsetting;
 	} *interface;
-} __packed;
+} __attribute__((packed));
 #define USB_DT_CONFIGURATION_SIZE		9
 
 /* USB Configuration Descriptor bmAttributes bit definitions */
@@ -194,7 +194,7 @@ struct usb_interface_descriptor {
 	const struct usb_endpoint_descriptor *endpoint;
 	const void *extra;
 	int extralen;
-} __packed;
+} __attribute__((packed));
 #define USB_DT_INTERFACE_SIZE			9
 
 /* USB Standard Endpoint Descriptor - Table 9-13 */
@@ -205,7 +205,7 @@ struct usb_endpoint_descriptor {
 	uint8_t bmAttributes;
 	uint16_t wMaxPacketSize;
 	uint8_t bInterval;
-} __packed;
+} __attribute__((packed));
 #define USB_DT_ENDPOINT_SIZE		sizeof(struct usb_endpoint_descriptor)
 
 /* USB Endpoint Descriptor bmAttributes bit definitions */
@@ -230,7 +230,7 @@ struct usb_string_descriptor {
 	uint8_t bLength;
 	uint8_t bDescriptorType;
 	uint16_t wData[];
-} __packed;
+} __attribute__((packed));
 
 /* From ECN: Interface Association Descriptors, Table 9-Z */
 struct usb_iface_assoc_descriptor {
@@ -242,7 +242,7 @@ struct usb_iface_assoc_descriptor {
 	uint8_t bFunctionSubClass;
 	uint8_t bFunctionProtocol;
 	uint8_t iFunction;
-} __packed;
+} __attribute__((packed));
 #define USB_DT_INTERFACE_ASSOCIATION_SIZE \
 				sizeof(struct usb_iface_assoc_descriptor)
 
diff --git a/lib/usb/usb_private.h b/lib/usb/usb_private.h
index 802f7c67..6d226681 100644
--- a/lib/usb/usb_private.h
+++ b/lib/usb/usb_private.h
@@ -69,7 +69,7 @@ struct _usbd_device {
 			DATA_IN, LAST_DATA_IN, STATUS_IN,
 			DATA_OUT, LAST_DATA_OUT, STATUS_OUT,
 		} state;
-		struct usb_setup_data req __aligned(4);
+		struct usb_setup_data req __attribute__((aligned(4)));
 		uint8_t *ctrl_buf;
 		uint16_t ctrl_len;
 		void (*complete)(usbd_device *usbd_dev,