stepcompress: Modify check_expand() into check_push()

Add the new item at the same time as checking if there is space in the
queue.

Also, update the default optimization level of c_helper.so to O2 to
improve the compiled code layout.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/chelper.py

@@ -6,7 +6,7 @@
 import os, logging
 import cffi
 
-COMPILE_CMD = "gcc -Wall -g -O -shared -fPIC -o %s %s"
+COMPILE_CMD = "gcc -Wall -g -O2 -shared -fPIC -o %s %s"
 SOURCE_FILES = ['stepcompress.c', 'serialqueue.c', 'pyhelper.c']
 DEST_LIB = "c_helper.so"
 OTHER_FILES = ['list.h', 'serialqueue.h', 'pyhelper.h']