I've generated Spigot with BuildTools using java -jar BuildTools.jar --rev 1.12. I get the same error every time.

C:\Users\Ceathen\AppData\Local\McMyAdmin\Minecraft>java -Xms1024M -Xmx2048M -jar spigot-1.12.jar nogui
Loading libraries, please wait...
[22:31:04 INFO]: Starting minecraft server version 1.12
[22:31:04 INFO]: Loading properties
[22:31:04 INFO]: Default game type: SURVIVAL
[22:31:04 INFO]: This server is running CraftBukkit version git-Spigot-4df3c0c-03f1e37 (MC: 1.12) (Implementing API version 1.12-R0.1-SNAPSHOT)
[22:31:04 ERROR]: Encountered an unexpected exception
com.google.gson.JsonParseException: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
at net.minecraft.server.v1_12_R1.ChatDeserializer.a(SourceFile:506) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.ChatDeserializer.a(SourceFile:522) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.JsonList.load(JsonList.java:174) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.DedicatedPlayerList.A(SourceFile:99) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.DedicatedPlayerList.<init>(SourceFile:25) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.DedicatedServer.init(DedicatedServer.java:183) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:544) [spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at java.lang.Thread.run(Unknown Source) [?:1.8.0_131]
Caused by: com.google.gson.stream.MalformedJsonException: Use JsonReader.setLenient(true) to accept malformed JSON at line 1 column 1 path $
at com.google.gson.stream.JsonReader.syntaxError(JsonReader.java:1559) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at com.google.gson.stream.JsonReader.checkLenient(JsonReader.java:1401) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:593) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at com.google.gson.stream.JsonReader.peek(JsonReader.java:425) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:74) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at com.google.gson.internal.bind.CollectionTypeAdapterFactory$Adapter.read(CollectionTypeAdapterFactory.java:61) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
at net.minecraft.server.v1_12_R1.ChatDeserializer.a(SourceFile:504) ~[spigot-1.12.jar:git-Spigot-4df3c0c-03f1e37]
... 7 more
>
C:\Users\Ceathen\AppData\Local\McMyAdmin\Minecraft>pause
Press any key to continue . . .