Fix an invalid check for duplicate option categories.

Summary:
The check performed in the comparator is invalid, as some STL
implementations enforce strict weak ordering by calling the comparator with the
same value. This check was also in a wrong place: the assertion would only fire
when -help was used. The new check is performed each time the category is
registered (we are not going to have thousands of them, so it's fine to do it in
O(N^2)).

Reviewers: jordan_rose

Reviewed By: jordan_rose

CC: cfe-commits, alexmc

Differential Revision: http://llvm-reviews.chandlerc.com/D2699

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200853 91177308-0d34-0410-b5e6-96231b3b80d8
[mips] Add NaCl target and forbid indexed loads and stores for it

This patch adds NaCl target for Mips. It also forbids indexed loads and
stores if the target is NaCl.

Patch by Sasa Stankovic.

Differential Revision: http://llvm-reviews.chandlerc.com/D2690


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200855 91177308-0d34-0410-b5e6-96231b3b80d8
Revert "Fix an invalid check for duplicate option categories."

This reverts commit r200853.

It was causing clang/Analysis/checker-plugins.c to crash.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200858 91177308-0d34-0410-b5e6-96231b3b80d8