libc: Stub out tmpfile() as well as add an empty math.h

libs/libc/include/stdio.h

@@ -162,6 +162,8 @@ extern "C"
 
     int remove(const char* pathname); // Not implemented.
 
+    FILE* tmpfile(void); // Not implemented.
+
 #ifdef __cplusplus
 }
 #endif

libs/libc/src/stdio.cpp

@@ -58,4 +58,10 @@ extern "C"
     {
         NOT_IMPLEMENTED("sscanf");
     }
+
+    FILE* tmpfile()
+    {
+        errno = ENOTSUP;
+        return NULL;
+    }
 }