diff --git a/include/mimalloc.h b/include/mimalloc.h
index b4f24137..ec579304 100644
--- a/include/mimalloc.h
+++ b/include/mimalloc.h
@@ -24,7 +24,7 @@ terms of the MIT license. A copy of the license can be found in the file
   #define mi_attr_noexcept
 #endif
 
-#if (__cplusplus >= 201703)
+#if defined(__cplusplus) && (__cplusplus >= 201703)
   #define mi_decl_nodiscard    [[nodiscard]]
 #elif (__GNUC__ >= 4) || defined(__clang__)  // includes clang, icc, and clang-cl
   #define mi_decl_nodiscard    __attribute__((warn_unused_result))
diff --git a/src/alloc-posix.c b/src/alloc-posix.c
index 4395893b..1ba1509b 100644
--- a/src/alloc-posix.c
+++ b/src/alloc-posix.c
@@ -20,6 +20,10 @@ terms of the MIT license. A copy of the license can be found in the file
 #include <string.h>  // memcpy
 #include <stdlib.h>  // getenv
 
+#ifdef _MSC_VER
+#pragma warning(disable:4996)  // getenv _wgetenv
+#endif
+
 #ifndef EINVAL
 #define EINVAL 22
 #endif
@@ -111,8 +115,7 @@ mi_decl_restrict unsigned char* mi_mbsdup(const unsigned char* s)  mi_attr_noexc
 int mi_dupenv_s(char** buf, size_t* size, const char* name) mi_attr_noexcept {
   if (buf==NULL || name==NULL) return EINVAL;
   if (size != NULL) *size = 0;
-  #pragma warning(suppress:4996)
-  char* p = getenv(name);
+  char* p = getenv(name);        // mscver warning 4996
   if (p==NULL) {
     *buf = NULL;
   }
@@ -132,8 +135,7 @@ int mi_wdupenv_s(unsigned short** buf, size_t* size, const unsigned short* name)
   *buf = NULL;
   return EINVAL;
 #else
-  #pragma warning(suppress:4996)
-  unsigned short* p = (unsigned short*)_wgetenv((const wchar_t*)name);
+  unsigned short* p = (unsigned short*)_wgetenv((const wchar_t*)name);  // msvc warning 4996
   if (p==NULL) {
     *buf = NULL;
   }
diff --git a/src/options.c b/src/options.c
index 4c45d6e5..c13871d8 100644
--- a/src/options.c
+++ b/src/options.c
@@ -14,6 +14,11 @@ terms of the MIT license. A copy of the license can be found in the file
 #include <ctype.h>  // toupper
 #include <stdarg.h>
 
+#ifdef _MSC_VER
+#pragma warning(disable:4996)   // strncpy, strncat
+#endif
+
+
 static uintptr_t mi_max_error_count = 16;  // stop outputting errors after this
 
 static void mi_add_stderr_output();
@@ -217,7 +222,6 @@ static void mi_out_buf_stderr(const char* msg, void* arg) {
 
 // Should be atomic but gives errors on many platforms as generally we cannot cast a function pointer to a uintptr_t.
 // For now, don't register output from multiple threads.
-#pragma warning(suppress:4180)
 static mi_output_fun* volatile mi_out_default; // = NULL
 static _Atomic(void*) mi_out_arg; // = NULL
 
@@ -391,13 +395,11 @@ void _mi_error_message(int err, const char* fmt, ...) {
 
 static void mi_strlcpy(char* dest, const char* src, size_t dest_size) {
   dest[0] = 0;
-  #pragma warning(suppress:4996)
   strncpy(dest, src, dest_size - 1);
   dest[dest_size - 1] = 0;
 }
 
 static void mi_strlcat(char* dest, const char* src, size_t dest_size) {
-  #pragma warning(suppress:4996)
   strncat(dest, src, dest_size - 1);
   dest[dest_size - 1] = 0;
 }
@@ -424,7 +426,7 @@ static bool mi_getenv(const char* name, char* result, size_t result_size) {
 #elif !defined(MI_USE_ENVIRON) || (MI_USE_ENVIRON!=0)
 // On Posix systemsr use `environ` to acces environment variables 
 // even before the C runtime is initialized.
-#if defined(__APPLE__)
+#if defined(__APPLE__) && defined(__has_include) && __has_include(<crt_externs.h>)
 #include <crt_externs.h>
 static char** mi_get_environ(void) {
   return (*_NSGetEnviron());
diff --git a/src/os.c b/src/os.c
index 46739cd9..f99c11c1 100644
--- a/src/os.c
+++ b/src/os.c
@@ -22,6 +22,10 @@ terms of the MIT license. A copy of the license can be found in the file
 
 #include <string.h>  // strerror
 
+#ifdef _MSC_VER
+#pragma warning(disable:4996)  // strerror
+#endif
+
 
 #if defined(_WIN32)
 #include <Windows.h>
@@ -229,7 +233,6 @@ static bool mi_os_mem_free(void* addr, size_t size, bool was_committed, mi_stats
   if (was_committed) _mi_stat_decrease(&stats->committed, size);
   _mi_stat_decrease(&stats->reserved, size);
   if (err) {
-    #pragma warning(suppress:4996)
     _mi_warning_message("munmap failed: %s, addr 0x%8li, size %lu\n", strerror(errno), (size_t)addr, size);
     return false;
   }
diff --git a/test/main-override-static.c b/test/main-override-static.c
index aee28156..ca65a0b2 100644
--- a/test/main-override-static.c
+++ b/test/main-override-static.c
@@ -176,6 +176,8 @@ static void double_free2();
 static void corrupt_free();
 static void block_overflow1();
 static void invalid_free();
+static void test_aslr(void);
+
 
 
 int main() {
@@ -185,7 +187,8 @@ int main() {
   // double_free1();
   // double_free2();
   // corrupt_free();
-  //block_overflow1();
+  // block_overflow1();
+  // test_aslr();
   invalid_free();
 
   void* p1 = malloc(78);
@@ -287,3 +290,10 @@ static void corrupt_free() {
     malloc(SZ);
   }
 }
+
+static void test_aslr(void) {
+  void* p[256];
+  p[0] = malloc(378200);
+  p[1] = malloc(1134626);
+  printf("p1: %p, p2: %p\n", p[0], p[1]);
+}