Wireguard not building on pre-rc1 4.19 kernels (Fedora)

[Bruno Wolff III]

[bruno at cerberus src]$ make KERNELDIR=/lib/modules/4.19.0-0.rc0.git6.1.fc30.x86_64/build clean all
  CLEAN   /home/bruno/WireGuard/src/.tmp_versions
  CLEAN   /home/bruno/WireGuard/src/tools/{wg,*.o,*.d}
  CC [M]  /home/bruno/WireGuard/src/main.o
In file included from <command-line>:
/home/bruno/WireGuard/src/compat/compat.h:684:20: error: static declaration of ‘rng_is_initialized’ follows non-static declaration
 static inline bool rng_is_initialized(void)
                    ^~~~~~~~~~~~~~~~~~
In file included from ./include/linux/net.h:22,
                 from ./include/linux/skbuff.h:29,
                 from ./include/linux/ip.h:20,
                 from /home/bruno/WireGuard/src/compat/compat.h:640,
                 from <command-line>:
./include/linux/random.h:39:13: note: previous declaration of ‘rng_is_initialized’ was here
 extern bool rng_is_initialized(void);
             ^~~~~~~~~~~~~~~~~~
make[2]: *** [scripts/Makefile.build:311: /home/bruno/WireGuard/src/main.o] Error 1
make[1]: *** [Makefile:1514: _module_/home/bruno/WireGuard/src] Error 2
make: *** [Makefile:36: module] Error 2
[bruno at cerberus src]$