Who needs that $(CLANGDIR)/tools/clang/include anyway?

It was included ever since 02a8d36e "initial
support for clang compiler plugins" but will probably point at either a non-
existing dir or a dir in the Clang source tree (that does not even contain all
the include files that the corresponding installation dir would contain, as some
include files are generated during the build).  For a properly installed LLVM/
Clang, all include files should be found underneath a single include/ dir.

Change-Id: Ie23cb1ae701eed1ee78448eb6c828d07b15121c2

compilerplugins/Makefile-clang.mk

@@ -25,8 +25,7 @@ CLANGCXXFLAGS=-O2 -Wall -Wextra -Wundef -g
 # Clang headers require these.
 CLANGDEFS=-D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -fno-rtti
 # All include locations needed.
-CLANGINCLUDES=$(if $(filter /usr,$(CLANGDIR)),,-isystem $(CLANGDIR)/include) \
-			  -isystem $(CLANGDIR)/tools/clang/include
+CLANGINCLUDES=$(if $(filter /usr,$(CLANGDIR)),,-isystem $(CLANGDIR)/include)
 
 # Clang/LLVM libraries are intentionally not linked in, they are usually built as static libraries, which means the resulting
 # plugin would be big (even though the clang binary already includes it all) and it'd be necessary to explicitly specify