Issues compiling on linux


```
$ make
src/getopt.h:64:10: fatal error: crtdefs.h: No such file or directory
   64 | #include <crtdefs.h>
      |          ^~~~~~~~~~~
```

My environment:
```
$ uname --all
Linux abe 5.7.5-arch1-1 #1 SMP PREEMPT Mon, 22 Jun 2020 08:10:02 +0000 x86_64 GNU/Linux
```


For a workarrond see [my fork](https://github.com/o3o/texpack)

Thank you very much