Subzero: Include commit count in revision string.

Makefile.standalone

 # The following variables will likely need to be modified, depending on where
 # and how you built LLVM & Clang. They can be overridden in a command-line
 # invocation of make, like:
 #
 #   make LLVM_SRC_PATH=<path> LIBCXX_INSTALL_PATH=<path> CLANG_PATH=<path> \
 #        PNACL_BIN_PATH=<path> ...
 #
 
 # LLVM_SRC_PATH is the path to the root of the checked out source code. This
 # directory should contain the configure script, the include/ and lib/
@@ skipping 93 matching lines @@
 #   SZTARGET=ARM32
 #   SZTARGET=MIPS32
 #   SZTARGET=X8632
 #   SZTARGET=X8664
 ifdef SZTARGET
   OBJDIR := $(OBJDIR)+T_$(SZTARGET)
   BASE_CXX_DEFINES += -DSZTARGET=$(SZTARGET)
 endif
 
 BASE_CXX_DEFINES += -DPNACL_LLVM
-BASE_CXX_DEFINES += -DSUBZERO_REVISION=$(shell git rev-parse HEAD)
+SZ_COMMIT_COUNT := $(shell git rev-list --count HEAD)
+SZ_GIT_HASH := $(shell git rev-parse HEAD)
+BASE_CXX_DEFINES += -DSUBZERO_REVISION=$(SZ_COMMIT_COUNT)_$(SZ_GIT_HASH)
 
 CXX_DEFINES := $(BASE_CXX_DEFINES) -DPNACL_BROWSER_TRANSLATOR=0
 
 ifdef NOASSERT
   ASSERTIONS = -DNDEBUG
 else
   ASSERTIONS =
   OBJDIR := $(OBJDIR)+Asserts
 endif
 
@@ skipping 666 matching lines @@
 
 help-check-xtest:
         @cat Makefile.standalone-help/check-xtest.txt
 
 clean:
         rm -rf pnacl-sz *.o $(foreach nexe,$(NEXES),$(notdir $(nexe))) \
           $(OBJDIR) $(SB_OBJDIR) $(SBB_OBJDIR) build/*.bloat.json
 
 clean-all: clean
         rm -rf build/ crosstest/Output/