chore(build.sh): cmake should clean first

build.sh

@@ -1,11 +1,9 @@
 #!/usr/bin/env bash
 
-BUILD_PATH="_build/"
+build_tmp="_build/"
 
-if [ ! -e $BUILD_PATH ]; then
+mkdir ${build_tmp} 2>/dev/null
-    mkdir $BUILD_PATH
+cd ${build_tmp}
-fi
 
-cd _build/
+cmake --clean-first ..
-cmake ../
+make -j 4 --makefile Makefile
-make -j 4