More compat work.

Move syscall to int 0x82 since using int 0x80 was kinda prone to fork bombs
when building things on Linux. :^)

LibC/stdlib.cpp

@@ -201,6 +201,11 @@ char* getenv(const char* name)
     return nullptr;
 }
 
+int putenv(char*)
+{
+    assert(false);
+}
+
 double atof(const char*)
 {
     assert(false);