diff --git a/demos/constants.c b/demos/constants.c
index d5d3622..f747eb5 100644
--- a/demos/constants.c
+++ b/demos/constants.c
@@ -8,7 +8,7 @@
  */
 #include "tomcrypt.h"
 
-#if _POSIX_C_SOURCE >= 200112L
+#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
 #include <libgen.h>
 #else
 #define basename(x) x
diff --git a/demos/hashsum.c b/demos/hashsum.c
index 164bd68..aee0bd2 100644
--- a/demos/hashsum.c
+++ b/demos/hashsum.c
@@ -18,7 +18,7 @@
 
 #include <tomcrypt.h>
 
-#if _POSIX_C_SOURCE >= 200112L
+#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
 #include <libgen.h>
 #else
 #define basename(x) x
diff --git a/demos/sizes.c b/demos/sizes.c
index c2c07ef..54d1979 100644
--- a/demos/sizes.c
+++ b/demos/sizes.c
@@ -9,7 +9,7 @@
 
 #include "tomcrypt.h"
 
-#if _POSIX_C_SOURCE >= 200112L
+#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
 #include <libgen.h>
 #else
 #define basename(x) x
diff --git a/src/misc/hkdf/hkdf_test.c b/src/misc/hkdf/hkdf_test.c
index f3d5811..0c58255 100644
--- a/src/misc/hkdf/hkdf_test.c
+++ b/src/misc/hkdf/hkdf_test.c
@@ -265,7 +265,7 @@ int hkdf_test(void)
                         cases[i].info, cases[i].info_l,
                         cases[i].IKM,   cases[i].IKM_l,
                         OKM, cases[i].OKM_l)) != CRYPT_OK) {
-#if LTC_TEST_DBG > 1
+#if defined(LTC_TEST_DBG) && (LTC_TEST_DBG > 1)
             printf("LTC_HKDF-%s test #%d, %s\n", cases[i].Hash, i, error_to_string(err));
 #endif
             return err;