add preload check to options initialization

src/options.c

@@ -367,6 +367,10 @@ static bool mi_getenv(const char* name, char* result, size_t result_size) {
 }
 #endif
 static void mi_option_init(mi_option_desc_t* desc) {
+  #ifndef _WIN32
+  // cannot call getenv() when still initializing the C runtime.
+  if (_mi_preloading()) return;
+  #endif
   // Read option value from the environment
   char buf[64+1];
   mi_strlcpy(buf, "mimalloc_", sizeof(buf));