diff --git a/mjs.c b/mjs.c
index 49c3d92..262707c 100644
--- a/mjs.c
+++ b/mjs.c
@@ -1145,7 +1145,9 @@ int gettimeofday(struct timeval *tp, void *tzp);
 /*
  * ARM C Compiler doesn't have strdup, so we provide it
  */
-#define CS_ENABLE_STRDUP defined(__ARMCC_VERSION)
+#if defined(__ARMCC_VERSION)
+#define CS_ENABLE_STRDUP 1
+#endif
 
 #endif /* CS_PLATFORM == CS_P_NRF51 */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_NRF51_H_ */
@@ -1189,7 +1191,9 @@ int gettimeofday(struct timeval *tp, void *tzp);
 /*
  * ARM C Compiler doesn't have strdup, so we provide it
  */
-#define CS_ENABLE_STRDUP defined(__ARMCC_VERSION)
+#if defined(__ARMCC_VERSION)
+#define CS_ENABLE_STRDUP 1
+#endif
 
 #endif /* CS_PLATFORM == CS_P_NRF52 */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_NRF52_H_ */
diff --git a/src/common/platforms/platform_nrf51.h b/src/common/platforms/platform_nrf51.h
index 6f1357b..2f04c07 100644
--- a/src/common/platforms/platform_nrf51.h
+++ b/src/common/platforms/platform_nrf51.h
@@ -48,7 +48,9 @@ int gettimeofday(struct timeval *tp, void *tzp);
 /*
  * ARM C Compiler doesn't have strdup, so we provide it
  */
-#define CS_ENABLE_STRDUP defined(__ARMCC_VERSION)
+#if defined(__ARMCC_VERSION)
+#define CS_ENABLE_STRDUP 1
+#endif
 
 #endif /* CS_PLATFORM == CS_P_NRF51 */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_NRF51_H_ */
diff --git a/src/common/platforms/platform_nrf52.h b/src/common/platforms/platform_nrf52.h
index 2b8b882..0cd12bb 100644
--- a/src/common/platforms/platform_nrf52.h
+++ b/src/common/platforms/platform_nrf52.h
@@ -51,7 +51,9 @@
 /*
  * ARM C Compiler doesn't have strdup, so we provide it
  */
-#define CS_ENABLE_STRDUP defined(__ARMCC_VERSION)
+#if defined(__ARMCC_VERSION)
+#define CS_ENABLE_STRDUP 1
+#endif
 
 #endif /* CS_PLATFORM == CS_P_NRF52 */
 #endif /* CS_COMMON_PLATFORMS_PLATFORM_NRF52_H_ */