When building StaticAnalyzer/Frontend add -I "<Checkers build dir>" to allow Checkers.inc to be
included without '..', thus being compatible with build systems of *BSDs.

Patch by Joerg Sonnenberger!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125758 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Frontend/Makefile b/lib/StaticAnalyzer/Frontend/Makefile
index 1e6561e..2698120 100644
--- a/lib/StaticAnalyzer/Frontend/Makefile
+++ b/lib/StaticAnalyzer/Frontend/Makefile
@@ -14,4 +14,6 @@
 CLANG_LEVEL := ../../..
 LIBRARYNAME := clangStaticAnalyzerFrontend
 
+CPP.Flags += -I${PROJ_OBJ_DIR}/../Checkers
+
 include $(CLANG_LEVEL)/Makefile