diff --git a/projects/python3-libraries/build.sh b/projects/python3-libraries/build.sh
index 58be24737..c3cf7f195 100755
--- a/projects/python3-libraries/build.sh
+++ b/projects/python3-libraries/build.sh
@@ -52,7 +52,7 @@ cp $SRC/python-library-fuzzers/python_coverage.h Python/
 sed -i '1 s/^.*$/#include "python_coverage.h"/g' Python/ceval.c
 sed -i 's/case TARGET\(.*\): {/\0\nfuzzer_record_code_coverage(f->f_code, f->f_lasti);/g' Python/ceval.c
 
-./configure "${FLAGS[@]}" --prefix=$CPYTHON_INSTALL_PATH
+./configure "${FLAGS[@]+"${FLAGS[@]}"}" --prefix=$CPYTHON_INSTALL_PATH
 make -j$(nproc)
 make install