--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,13 +1,14 @@
 dnl
 dnl Local autoconf macros used with mozilla
 dnl The contents of this file are under the Public Domain.
 dnl
 
+builtin(include, mozilla/build/autoconf/ccache.m4)dnl
 builtin(include, mozilla/build/autoconf/config.status.m4)dnl
 builtin(include, mozilla/build/autoconf/nspr.m4)dnl
 builtin(include, mozilla/build/autoconf/nss.m4)dnl
 builtin(include, mozilla/build/autoconf/pkg.m4)dnl
 builtin(include, mozilla/build/autoconf/codeset.m4)dnl
 builtin(include, mozilla/build/autoconf/altoptions.m4)dnl
 builtin(include, mozilla/build/autoconf/mozprog.m4)dnl
 builtin(include, mozilla/build/autoconf/acwinpaths.m4)dnl

--- a/config/autoconf.mk.in
+++ b/config/autoconf.mk.in
@@ -71,16 +71,18 @@ MOZ_DEBUG_LDFLAGS=@MOZ_DEBUG_LDFLAGS@
 MOZ_JSDEBUGGER  = @MOZ_JSDEBUGGER@
 MOZ_MEMORY      = @MOZ_MEMORY@
 MOZ_PROFILING   = @MOZ_PROFILING@
 MOZ_ENABLE_PROFILER_SPS = @MOZ_ENABLE_PROFILER_SPS@
 MOZ_JPROF       = @MOZ_JPROF@
 MOZ_SHARK       = @MOZ_SHARK@
 DEHYDRA_PATH    = @DEHYDRA_PATH@
 
+MOZ_USING_CCACHE = @MOZ_USING_CCACHE@
+CLANG_CXX = @CLANG_CXX@
 NS_TRACE_MALLOC = @NS_TRACE_MALLOC@
 USE_ELF_DYNSTR_GC = @USE_ELF_DYNSTR_GC@
 INCREMENTAL_LINKER = @INCREMENTAL_LINKER@
 MACOSX_DEPLOYMENT_TARGET = @MACOSX_DEPLOYMENT_TARGET@
 MOZ_CALENDAR	= @MOZ_CALENDAR@
 MOZ_PLAINTEXT_EDITOR_ONLY = @MOZ_PLAINTEXT_EDITOR_ONLY@
 MOZ_COMPOSER = @MOZ_COMPOSER@
 ENABLE_TESTS	= @ENABLE_TESTS@

--- a/config/config.mk
+++ b/config/config.mk
@@ -493,16 +493,23 @@ endif # NEXT_ROOT
 PBBUILD_SETTINGS = GCC_VERSION="$(GCC_VERSION)" SYMROOT=build ARCHS="$(OS_TEST)"
 ifdef MACOS_SDK_DIR
 PBBUILD_SETTINGS += SDKROOT="$(MACOS_SDK_DIR)"
 endif # MACOS_SDK_DIR
 ifdef MACOSX_DEPLOYMENT_TARGET
 export MACOSX_DEPLOYMENT_TARGET
 PBBUILD_SETTINGS += MACOSX_DEPLOYMENT_TARGET="$(MACOSX_DEPLOYMENT_TARGET)"
 endif # MACOSX_DEPLOYMENT_TARGET
+
+ifdef MOZ_USING_CCACHE
+ifdef CLANG_CXX
+export CCACHE_CPP2=1
+endif
+endif
+
 ifdef MOZ_OPTIMIZE
 ifeq (2,$(MOZ_OPTIMIZE))
 # Only override project defaults if the config specified explicit settings
 PBBUILD_SETTINGS += GCC_MODEL_TUNING= OPTIMIZATION_CFLAGS="$(MOZ_OPTIMIZE_FLAGS)"
 endif # MOZ_OPTIMIZE=2
 endif # MOZ_OPTIMIZE
 endif # OS_ARCH=Darwin
 

--- a/configure.in
+++ b/configure.in
@@ -345,69 +345,17 @@ else
     if test -z "$HOST_AR"; then
         HOST_AR='$AR'
     fi
     if test -z "$HOST_AR_FLAGS"; then
         HOST_AR_FLAGS='$AR_FLAGS'
     fi
 fi
 
-GNU_AS=
-GNU_LD=
-GNU_CC=
-GNU_CXX=
-CC_VERSION='N/A'
-CXX_VERSION='N/A'
-if test "$GCC" = "yes"; then
-    GNU_CC=1
-    CC_VERSION=`$CC -v 2>&1 | grep 'gcc version'`
-fi
-if test "$GXX" = "yes"; then
-    GNU_CXX=1
-    CXX_VERSION=`$CXX -v 2>&1 | grep 'gcc version'`
-fi
-if test "`echo | $AS -v 2>&1 | grep -c GNU`" != "0"; then
-    GNU_AS=1
-fi
-if test "`echo | $LD -v 2>&1 | grep -c GNU`" != "0"; then
-    GNU_LD=1
-fi
-if test "$GNU_CC"; then
-    if `$CC -print-prog-name=ld` -v 2>&1 | grep -c GNU >/dev/null; then
-        GCC_USE_GNU_LD=1
-    fi
-fi
-
-INTEL_CC=
-INTEL_CXX=
-if test "$GCC" = yes; then
-   if test "`$CC -help 2>&1 | grep -c 'Intel(R) C++ Compiler'`" != "0"; then
-     INTEL_CC=1
-   fi
-fi
-
-if test "$GXX" = yes; then
-   if test "`$CXX -help 2>&1 | grep -c 'Intel(R) C++ Compiler'`" != "0"; then
-     INTEL_CXX=1
-   fi
-fi
-
-CLANG_CC=
-CLANG_CXX=
-if test "$GCC" = yes; then
-   if test "`$CC -v 2>&1 | grep -c 'clang version'`" != "0"; then
-     CLANG_CC=1
-   fi
-fi
-
-if test "$GXX" = yes; then
-   if test "`$CXX -v 2>&1 | grep -c 'clang version'`" != "0"; then
-     CLANG_CXX=1
-   fi
-fi
+MOZ_TOOL_VARIABLES
 
 dnl Special win32 checks
 dnl ========================================================
 case "$target" in
 *-wince|*-winmo)
     WINVER=500
     ;;
 *)
@@ -5894,42 +5842,17 @@ MOZ_ARG_ENABLE_BOOL(shark,
 [  --enable-shark          Enable shark remote profiling (needs CHUD framework). Implies --enable-profiling.],
     MOZ_SHARK=1,
     MOZ_SHARK= )
 if test -n "$MOZ_SHARK"; then
     MOZ_PROFILING=1
     AC_DEFINE(MOZ_SHARK)
 fi
 
-dnl ======================================================
-dnl = Enable compiling with ccache
-dnl ======================================================
-MOZ_ARG_WITH_STRING(ccache,
-[  --with-ccache[=path/to/ccache]
-                          Enable compiling with ccache],
-    CCACHE=$withval, CCACHE="no")
-
-if test "$CCACHE" != "no"; then
-    if test -z "$CCACHE" -o "$CCACHE" = "yes"; then
-        CCACHE=
-    else
-        if test ! -e "$CCACHE"; then
-            AC_MSG_ERROR([$CCACHE not found])
-        fi
-    fi
-    MOZ_PATH_PROGS(CCACHE, $CCACHE ccache)
-    if test -z "$CCACHE" -o "$CCACHE" = ":"; then
-        AC_MSG_ERROR([ccache not found])
-    elif test -x "$CCACHE"; then
-        CC="$CCACHE $CC"
-        CXX="$CCACHE $CXX"
-    else
-        AC_MSG_ERROR([$CCACHE is not executable])
-    fi
-fi
+MOZ_CHECK_CCACHE
 
 dnl ========================================================
 dnl = Enable static checking using gcc-dehydra
 dnl ========================================================
 
 MOZ_ARG_WITH_STRING(static-checking,
 [  --with-static-checking=path/to/gcc_dehydra.so
                             Enable static checking of code using GCC-dehydra],