Rename DEBUG macro to LLVM_DEBUG.
    
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
diff --git a/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp b/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
index 72b631b..dbc4581 100644
--- a/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
+++ b/llvm/lib/CodeGen/ResetMachineFunctionPass.cpp
@@ -55,7 +55,7 @@
               MachineFunctionProperties::Property::FailedISel)) {
         if (AbortOnFailedISel)
           report_fatal_error("Instruction selection failed");
-        DEBUG(dbgs() << "Resetting: " << MF.getName() << '\n');
+        LLVM_DEBUG(dbgs() << "Resetting: " << MF.getName() << '\n');
         ++NumFunctionsReset;
         MF.reset();
         if (EmitFallbackDiag) {