Add ccc-analyzer support for '-imacros'.  Fixes PR 7204.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105624 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/scan-build/ccc-analyzer b/tools/scan-build/ccc-analyzer
index 391ea57..803b5e9 100755
--- a/tools/scan-build/ccc-analyzer
+++ b/tools/scan-build/ccc-analyzer
@@ -320,6 +320,7 @@
   '-ffreestanding' => 0,
   '-include' => 1,
   '-idirafter' => 1,
+  '-imacros' => 1,
   '-iprefix' => 1,
   '-iquote' => 1,
   '-isystem' => 1,