.text' will not fit in region iram1_0_seg' with c modules

[burner-]

There has been earlier issues with same error message but I think this is different case.
If you use .c libraries iram gets full quite fast.
I note that there is at file packages\esp8266\hardware\esp8266\1.6.5-947-g39819f0\tools\sdk\ld\eagle.app.v6.common.ld
following line:
.cpp.o(.literal, .text_)
So I add also:
.c.o(.literal_, .text)
and it resolve my problem. I am not expert with c neither esp so I do not know is that bad setting as default. But if does not cause another problems then it can be good setting by default at future releases.

[igrr]

Applied this along with other changes in #857. Thanks!