How to use time.h and math.h in nrf connect sdk?

[Krumita]

1)I want to use "mktime" and "localtime" in my nrf52840 code ,how do i include time.h file?

2)I am using math.h file , in prj.conf i define "CONFIG_NEWLIB_LIBC=y"  but I continuously  get error as below ,how do i resolve it?

error:

/usr/include/math.h:415:33: error: '_Float128' is not supported on this target

415 | # define _Mdouble_ _Float128

[Krumita]

1)I want to use "mktime" and "localtime" in my nrf52840 code ,how do i include time.h file?

and i get 

error:

/usr/include/math.h:415:33: error: '_Float128' is not supported on this target

415 | # define _Mdouble_ _Float128

error after adding math.h , what is reason for it.