Fix unxepected ccache miss

.gitlab-ci.yml

 stages:
+  - prepare
   - linting
   - build
   - test
   - extra
 
+setenv:
+  stage: prepare
+  script:
+    - export CCACHE_NOHASHDIR=1
+    - export CCACHE_BASEDIR=${CI_PROJECT_DIR}
+
 cpplint:
   stage: linting
   script:

CMakeLists.txt

@@ -42,7 +42,9 @@ if(MACE_ENABLE_OPT_SIZE)
 endif(MACE_ENABLE_OPT_SIZE)
 
 # flags apply only to mace code (third_party excluded)
-set(MACE_CODE_CC_FLAGS "${MACE_CODE_CC_FLAGS} -Wall -Werror")
+# -Wno-error=unused-command-line-argument: official Android toolchain contains
+# unsupported argument and will break ccache preprocessor
+set(MACE_CODE_CC_FLAGS "${MACE_CODE_CC_FLAGS} -Wall -Werror -Wno-error=unused-command-line-argument")
 set(MACE_CODE_CC_FLAGS "${MACE_CODE_CC_FLAGS} -std=c++11 -D_GLIBCXX_USE_C99_MATH_TR1")
 
 if(IOS)

mace/core/quantize.h

@@ -100,7 +100,6 @@ inline void QuantizeMultiplier(double multiplier,
     ++*shift;
   }
   *output_multiplier = static_cast<int32_t>(qint);
-  MACE_CHECK(*output_multiplier <= std::numeric_limits<int32_t>::max());
 }
 
 inline void GetOutputMultiplierAndShift(