Use cgcc in the sparse target

cgcc is the recommended way to run sparse, since it provides
many -Defines suitable to the given gcc platform. For example,
on some Ubuntu/glibc versions, a plain sparse invocation gives
the following warning:

    "warning: This machine appears to be neither x86_64 nor i386."

Using "cgcc -no-compile" instead eliminates this warning.

Signed-off-by: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Acked-by: Andreas Ericsson <ae@op5.se>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

Makefile

@@ -38,7 +38,7 @@ apidocs:
 test: $(TEST_RUN)
 
 sparse:
-	sparse -DSPARSE_IS_RUNNING $(ALL_CFLAGS) $(SPARSE_FLAGS) $(SRC_C)
+	cgcc -no-compile -DSPARSE_IS_RUNNING $(ALL_CFLAGS) $(SPARSE_FLAGS) $(SRC_C)
 
 install-headers: $(PUBLIC_HEADERS)
 	@mkdir -p /tmp/gitinc/git