fix a sanitizer undefined issue

Signed-off-by: zhenweijin <zhenwei.jin@intel.com>

Author: kylo5aby

build-scripts/config_common.cmake

@@ -146,7 +146,7 @@ include (${WAMR_ROOT_DIR}/build-scripts/package.cmake)
 # Sanitizers
 
 if (NOT DEFINED WAMR_BUILD_SANITIZER)
-  set(WAMR_BUILD_SANITIZER $ENV{WAMR_BUILD_SANITIZER})
+  set(WAMR_BUILD_SANITIZER "$ENV{WAMR_BUILD_SANITIZER}")
 endif()
 
 if (NOT WAMR_BUILD_SANITIZER STREQUAL "")