Currently, if the gcc toolchain is relocated and installed from sstate, then you try and compile
preprocessed source (.i or .ii files), the compiler will try and access the builtin sysroot location 
rather than the --sysroot option specified on the commandline. If access to that directory is 
permission denied (unreadable), gcc will error.

This happens when ccache is in use due to the fact it uses preprocessed source files.

The fix below adds %I to the cpp-output spec macro so the default substitutions for -iprefix, 
-isystem, -isysroot happen and the correct sysroot is used.

[YOCTO #2074]

Upstream-Status: Pending

RP 2012/04/13

Index: gcc-4_6-branch/gcc/gcc.c
===================================================================
--- gcc-4_6-branch.orig/gcc/gcc.c	2012-04-13 12:24:37.939671140 +0000
+++ gcc-4_6-branch/gcc/gcc.c	2012-04-13 12:24:54.439670688 +0000
@@ -953,7 +953,7 @@
                     %W{o*:--output-pch=%*}}%V}}}}}}", 0, 0, 0},
   {".i", "@cpp-output", 0, 0, 0},
   {"@cpp-output",
-   "%{!M:%{!MM:%{!E:cc1 -fpreprocessed %i %(cc1_options) %{!fsyntax-only:%(invoke_as)}}}}", 0, 0, 0},
+   "%{!M:%{!MM:%{!E:cc1 -fpreprocessed %i %I %(cc1_options) %{!fsyntax-only:%(invoke_as)}}}}", 0, 0, 0},
   {".s", "@assembler", 0, 0, 0},
   {"@assembler",
    "%{!M:%{!MM:%{!E:%{!S:as %(asm_debug) %(asm_options) %i %A }}}}", 0, 0, 0},
Index: gcc-4_6-branch/gcc/cp/lang-specs.h
===================================================================
--- gcc-4_6-branch.orig/gcc/cp/lang-specs.h	2012-04-13 12:25:01.019670594 +0000
+++ gcc-4_6-branch/gcc/cp/lang-specs.h	2012-04-13 12:25:07.567670180 +0000
@@ -64,5 +64,5 @@
   {".ii", "@c++-cpp-output", 0, 0, 0},
   {"@c++-cpp-output",
    "%{!M:%{!MM:%{!E:\
-    cc1plus -fpreprocessed %i %(cc1_options) %2\
+    cc1plus -fpreprocessed %i %I %(cc1_options) %2\
     %{!fsyntax-only:%(invoke_as)}}}}", 0, 0, 0},