Readme changes, github actions ci, test (#1)

* Readme changes, github actions ci, test

* Std flag change for older GCC versions"

* Install gcc multilib

* test fix and formatting

* Don't segfault on nonexistant file and show error instead

* Update ci.yml

* PR comments

* remove silly bit

test/test.c

@@ -0,0 +1,6 @@
+float apple = 3.0f;
+float banana = 65.32f;
+
+int something(void) {
+    return (int)(apple * banana) % 11;
+}