fix(build.sh): better path strategy

build.sh

@@ -1,24 +1,34 @@
 #!/usr/bin/env bash
 
-__dirname=`dirname $0`
+cd `dirname $0`
+__dirname=`pwd`
+PLATFORM=`uname | awk '{print tolower($1)}'`
 BUILD_TMP_PATH=${__dirname}/_build
 
+BINARY_NAME=demo_${PLATFORM}_amd64
+BINARY_DIR=${__dirname}/bin
+BINARY_FULL_PATH=${BINARY_DIR}/${BINARY_NAME}
+
+BUILD_BINARY_FULL_PATH=${BUILD_TMP_PATH}/${BINARY_NAME}
+
 # cleanup
-rm -r bin/* 2>/dev/null
+if [ -f ${BUILD_BINARY_FULL_PATH} ];then
+  rm ${BUILD_BINARY_FULL_PATH}
+fi
 
 # create tmp dir for cmake
 mkdir -p ${BUILD_TMP_PATH}
 
-cd ${BUILD_TMP_PATH}
-
 # Generate Makefile
-cmake --clean-first -DCMAKE_BUILD_TYPE=Release ..
+cd ${BUILD_TMP_PATH}
+  cmake --clean-first -DCMAKE_BUILD_TYPE=Release ${__dirname}
+cd ${__dirname}
 
 # Compile
-if [ -f 'Makefile' ];then
-  make --jobs 4
+if [ $? -eq 0 ];then
+  make --jobs 4 --directory ${BUILD_TMP_PATH}
 fi
 
-if [ $? -eq 0 ];then
-  cp demo_*_amd64 ../bin
+if [ -f ${BUILD_BINARY_FULL_PATH} ];then
+  cp ${BUILD_BINARY_FULL_PATH} ${BINARY_DIR}
 fi