Different at least

cmcmanis@chuck-desktop:usb_cdcacm$ make
cdcacm.c:123:2: error: unknown field 'extralen' specified in initializer
  .extralen = sizeof(cdcacm_functional_descriptors)
  ^
In file included from /home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:42:0,
                 from cdcacm.c:23:
cdcacm.c: In function 'cdcacm_set_config':
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbstd.h:72:30: warning: passing argument 2 of 'usbd_register_control_callback' makes pointer from integer without a cast
 #define USB_REQ_TYPE_CLASS   0x20
                              ^
cdcacm.c:220:5: note: in expansion of macro 'USB_REQ_TYPE_CLASS'
     USB_REQ_TYPE_CLASS | USB_REQ_TYPE_INTERFACE,
     ^
In file included from cdcacm.c:23:0:
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:223:6: note: expected 'usbd_control_callback' but argument is of type 'int'
 void usbd_register_control_callback(usbd_device *usbd_dev,
      ^
cdcacm.c:218:2: error: too many arguments to function 'usbd_register_control_callback'
  usbd_register_control_callback(
  ^
In file included from cdcacm.c:23:0:
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:223:6: note: declared here
 void usbd_register_control_callback(usbd_device *usbd_dev,
      ^
cdcacm.c: In function 'main':
cdcacm.c:238:24: error: 'otgfs_usb_driver' undeclared (first use in this function)
  usbd_dev = usbd_init(&otgfs_usb_driver, &dev, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
                        ^
cdcacm.c:238:24: note: each undeclared identifier is reported only once for each function it appears in
cdcacm.c:238:48: warning: passing argument 3 of 'usbd_init' from incompatible pointer type
  usbd_dev = usbd_init(&otgfs_usb_driver, &dev, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
                                                ^
In file included from cdcacm.c:23:0:
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:173:14: note: expected 'uint8_t *' but argument is of type 'const struct usb_config_descriptor *'
 usbd_device* usbd_init(const usbd_driver *driver,
              ^
cdcacm.c:238:57: warning: passing argument 4 of 'usbd_init' makes integer from pointer without a cast
  usbd_dev = usbd_init(&otgfs_usb_driver, &dev, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
                                                         ^
In file included from cdcacm.c:23:0:
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:173:14: note: expected 'uint16_t' but argument is of type 'const char **'
 usbd_device* usbd_init(const usbd_driver *driver,
              ^
cdcacm.c:238:13: error: too many arguments to function 'usbd_init'
  usbd_dev = usbd_init(&otgfs_usb_driver, &dev, &config, usb_strings, 3, usbd_control_buffer, sizeof(usbd_control_buffer));
             ^
In file included from cdcacm.c:23:0:
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:173:14: note: declared here
 usbd_device* usbd_init(const usbd_driver *driver,
              ^
cdcacm.c:239:46: warning: passing argument 2 of 'usbd_register_set_config_callback' from incompatible pointer type
  usbd_register_set_config_callback(usbd_dev, cdcacm_set_config);
                                              ^
In file included from cdcacm.c:23:0:
/home/cmcmanis/src/kuldeep-loc3/include/libopencm3/usb/usbd.h:232:6: note: expected 'usbd_set_config_callback' but argument is of type 'void (*)(struct usbd_device *, uint16_t)'
 void usbd_register_set_config_callback(usbd_device *usbd_dev,
      ^
../../../../Makefile.rules:155: recipe for target 'cdcacm.o' failed
make: *** [cdcacm.o] Error 1
cmcmanis@chuck-desktop:usb_cdcacm$