having trouble building espruino for STM32F411DISCOVERY

Hello, I'm not at all familiar with compiling code, beyond some trusted AUR packages for Linux. All of this is quite foreign. After recieving this error, I went looking in espruino-master which i pulled down previously. I found many ".o" files adjacent to many like-named ".c" and ".h" files. Why are only a few of these ".o" files missing, while they're clearly needed to build a binary?

[user@hostname Espruino-master]$ sudo STM32F411DISCOVERY=1 RELEASE=1 WIZNET=1 make serialflash
[sudo] password for user: 
fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git

... more fatal errors ...

fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
fatal: Not a git repository (or any of the parent directories): .git
CC libs/network/wiznet/network_wiznet.o
In file included from /home/user/Downloads/Espruino-master/src/jsvar.h:17:0,
                 from /home/user/Downloads/Espruino-master/src/jsparse.h:17,
                 from /home/user/Downloads/Espruino-master/src/jsinteractive.h:17,
                 from libs/network/wiznet/network_wiznet.c:14:
/home/user/Downloads/Espruino-master/src/jsutils.h:20:20: fatal error: string.h: No such file or directory
 [#include](https://forum.espruino.com/search/?q=%23include) <string.h>
                    ^
compilation terminated.
make: *** [Makefile:1875: libs/network/wiznet/network_wiznet.o] Error 1
[user@hostname Espruino-master]$ 

Also noteworthy is that im using a FT232RL USB-Serial converter and plugging into a breadboard with bare STM32F411CEU6 broken out to 0.1". No peripherals, just the capacitors that ST and my 3.3V regulator calls for. Pin 44(BOOT0) is connected to 3.3V and pin 20(PB2) is connected to GND

Are Rx and Tx supposed to cross on their way from FT232RL to STM32?

Any pointers are appreciated, thank you