diff --git a/tests/Makefile.test b/tests/Makefile.test
index a043810..9676370 100644
--- a/tests/Makefile.test
+++ b/tests/Makefile.test
@@ -1,7 +1,7 @@
 ARCH = $(shell uname -m)
 ifneq ("$(ARCH)", "ppc64")
 ifneq ("$(ARCH)", "ppc64le")
-        CROSS_COMPILE = powerpc64le-linux-
+        CROSS_COMPILE ?= powerpc64le-linux-
         endif
         endif
 
diff --git a/tests/decrementer/decrementer.c b/tests/decrementer/decrementer.c
index 36ac922..2617a94 100644
--- a/tests/decrementer/decrementer.c
+++ b/tests/decrementer/decrementer.c
@@ -1,5 +1,4 @@
-#include <unistd.h>
-#include <string.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
 
diff --git a/tests/illegal/illegal.c b/tests/illegal/illegal.c
index 0778ffe..a1ea325 100644
--- a/tests/illegal/illegal.c
+++ b/tests/illegal/illegal.c
@@ -1,5 +1,4 @@
-#include <unistd.h>
-#include <string.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>
 
diff --git a/tests/sc/sc.c b/tests/sc/sc.c
index 67d80b9..2914291 100644
--- a/tests/sc/sc.c
+++ b/tests/sc/sc.c
@@ -1,5 +1,4 @@
-#include <unistd.h>
-#include <string.h>
+#include <stddef.h>
 #include <stdint.h>
 #include <stdbool.h>