Merge "Remove our binary of ccache"

# limitations under the License.

#

# We no longer provide a ccache prebuilt.

#

# Ours was old, and had a number of issues that triggered non-reproducible

# results and other failures. Newer ccache versions may fix some of those

# issues, but at the large scale of our build servers, we weren't seeing

# significant performance gains from using ccache -- you end up needing very

# good locality and/or very large caches if you're building many different

# configurations.

#

# Local no-change full rebuilds were showing better results, but why not just

# use incremental builds at that point?

#

# So if you still want to use ccache, continue setting USE_CCACHE, but also set

# the CCACHE_EXEC environment variable to the path to your ccache executable.

ifneq ($(CCACHE_EXEC),)

ifneq ($(filter-out false,$(USE_CCACHE)),)

  # The default check uses size and modification time, causing false misses

  # since the mtime depends when the repo was checked out

  # See http://petereisentraut.blogspot.com/2011/09/ccache-and-clang-part-2.html

  export CCACHE_CPP2 := true

  CCACHE_HOST_TAG := $(HOST_PREBUILT_TAG)

  ccache := prebuilts/misc/$(CCACHE_HOST_TAG)/ccache/ccache

  # Check that the executable is here.

  ccache := $(strip $(wildcard $(ccache)))

  ifdef ccache

  ifndef CC_WRAPPER

      CC_WRAPPER := $(ccache)

    CC_WRAPPER := $(CCACHE_EXEC)

  endif

  ifndef CXX_WRAPPER

      CXX_WRAPPER := $(ccache)

    CXX_WRAPPER := $(CCACHE_EXEC)

  endif

    ccache =

endif

endif