diff --git a/package/zlib/1.2.12/clang/install.sh b/package/zlib/1.2.12/clang/install.sh
index 71a4fa5983a6c33124a105144587313fcc7a24b4..a3f9874821737c013f723f8b4d68ee04499788dd 100755
--- a/package/zlib/1.2.12/clang/install.sh
+++ b/package/zlib/1.2.12/clang/install.sh
@@ -4,8 +4,10 @@ set -e
 zlib_ver='1.2.12'
 . ${DOWNLOAD_TOOL} -u https://zlib.net/fossils/zlib-${zlib_ver}.tar.gz
 cd ${JARVIS_TMP}
+rm -rf zlib-${zlib_ver}
+export FFLAGS="-O3 -fPIC" CFLAGS="-O3 -fPIC" CXXFLAGS="-O3 -fPIC"
 tar -xvf ${JARVIS_DOWNLOAD}/zlib-${zlib_ver}.tar.gz
 cd zlib-${zlib_ver}
-./configure --prefix=$1 FCFLAGS="-O3 -fPIC"
+./configure --prefix=$1 
 make -j
 make install