Add test for getpagesize()

tests/Makefile

@@ -112,6 +112,7 @@ NAMES=\
 	unistd/getcwd \
 	unistd/gethostname \
 	unistd/getid \
+	unistd/getpagesize \
 	unistd/link \
 	unistd/pathconf \
 	unistd/setid \

tests/unistd/getpagesize.c

@@ -0,0 +1,14 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "test_helpers.h"
+
+int main(void) {
+    errno = 0;
+    int getpagesize_result = getpagesize();
+    int getpagesize_errno = errno;
+    
+    printf("getpagesize(): %d, errno: %d = %s\n", getpagesize_result,
+        getpagesize_errno, strerror(getpagesize_errno));
+}