Error message: ld returned 1 exit status (using Arduino and ESP8266)

Hello :).

I have tried compiling my code, but the following error:

C:\Users\nanna\AppData\Local\Temp\buildb39ad8e752d487d12abae3a785f78780.tmp/arduino.ar(time.c.o): In function `time':

C:\Users\nanna\AppData\Local\Arduino15\packages\esp8266\hardware\esp8266\2.2.0\cores\esp8266/time.c:93: multiple definition of `time'

sketch\ESP_test.ino.cpp.o:C:\Users\nanna\Documents\Arduino\libraries\PJON-master/PJON.h:98: first defined here

c:/users/nanna/appdata/local/arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9-2/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/bin/ld.exe: Warning: size of symbol `time' changed from 4 in sketch\ESP_test.ino.cpp.o to 29 in C:\Users\nanna\AppData\Local\Temp\buildb39ad8e752d487d12abae3a785f78780.tmp/arduino.ar(time.c.o)

c:/users/nanna/appdata/local/arduino15/packages/esp8266/tools/xtensa-lx106-elf-gcc/1.20.0-26-gb404fb9-2/bin/../lib/gcc/xtensa-lx106-elf/4.8.2/../../../../xtensa-lx106-elf/bin/ld.exe: Warning: type of symbol `time' changed from 1 to 2 in C:\Users\nanna\AppData\Local\Temp\buildb39ad8e752d487d12abae3a785f78780.tmp/arduino.ar(time.c.o)

collect2.exe: error: ld returned 1 exit status

I know that it mens I have errrors, but I can't seem to understand what I'm supposed to change. Does anybody understand what Arduino is asking for?

I hope you can help me.
Cheers

Does anybody understand what Arduino is asking for?

The compiler seems to be complaining that there are multiple definitions of time, but unless you post your program I doubt if you will get any help.