limits.h currently interferes with Clang's limits.h. include_next
emits a warning because it is a GNU extension. Will re add this once
we figure out a good solution.
This reverts commits 13bbca8d694b4ef2ad03ec1805f07da8640c1a31,
002cba03298a7e8f0c1cadcb7996379e9ea5feff, and
0fb3066873fdfbe28dbb6409c58a8bff7cf208c6.
This header contains implementation specific constants.
The compiler already provides its own limits.h with numerical limits
conforming to freestanding ISO C. But it is missing extensions like
POSIX, and does for example not include <linux/limits.h> which is
expected on a Linux system, therefore, an LLVM libc implementation of
limits.h is needed for hosted (__STDC_HOSTED__) environments.
Reviewed By: michaelrj
Differential Revision: https://reviews.llvm.org/D156961