diff --git a/src/alloc-posix.c b/src/alloc-posix.c
index 4e844ba3..1f55b3a8 100644
--- a/src/alloc-posix.c
+++ b/src/alloc-posix.c
@@ -19,6 +19,7 @@ terms of the MIT license. A copy of the license can be found in the file
 
 #include <errno.h>
 #include <string.h>  // memcpy
+#include <stdlib.h>  // getenv
 
 #ifndef EINVAL
 #define EINVAL 22
@@ -115,7 +116,7 @@ int mi_dupenv_s(char** buf, size_t* size, const char* name) mi_attr_noexcept {
   #pragma warning(suppress:4996)
   char* p = getenv(name);
   if (p==NULL) {
-    *buf = NULL;    
+    *buf = NULL;
   }
   else {
     *buf = mi_strdup(p);
@@ -146,4 +147,3 @@ int mi_wdupenv_s(unsigned short** buf, size_t* size, const unsigned short* name)
   return 0;
 #endif
 }
-
diff --git a/test/test-stress.c b/test/test-stress.c
index b26dfd04..298e5a17 100644
--- a/test/test-stress.c
+++ b/test/test-stress.c
@@ -180,7 +180,7 @@ static DWORD WINAPI thread_entry(LPVOID param) {
 static void run_os_threads(size_t nthreads) {
   DWORD* tids = (DWORD*)malloc(nthreads * sizeof(DWORD));
   HANDLE* thandles = (HANDLE*)malloc(nthreads * sizeof(HANDLE));
-  for (intptr_t i = 0; i < nthreads; i++) {
+  for (uintptr_t i = 0; i < nthreads; i++) {
     thandles[i] = CreateThread(0, 4096, &thread_entry, (void*)(i), 0, &tids[i]);
   }
   for (int i = 0; i < nthreads; i++) {