int_sqrt.c: Correction square root algo with naming
lib: Use glibc instead arch lib.
Conflicts:

	arch/arm/lib/Makefile
	lib/string.c
Revert "lib: Use glibc instead arch lib."

This reverts commit 952b93a84fae9e37c524aa8ae2fbca69e644c1b5.
int_sqrt: Improve 3x faster integer sqrt.

Result on 10,000,000 call.
Old:
sqrt(12345689) = 3513
real	0m0.768s
user	0m0.760s
sys	0m0.004s

New:
sqrt(12345689) = 3513
real	0m0.222s
user	0m0.224s
sys	0m0.000s