Merge branch 'static-assert' into 'master'

Implement static_assert

See merge request redox-os/relibc!1355

src/header/assert/cbindgen.toml

@@ -12,6 +12,10 @@ trailer = """
 #undef assert
 #endif
 
+#if __STDC_VERSION__ >= 201112L && !defined(__cplusplus)
+#define static_assert _Static_assert
+#endif
+
 #ifdef NDEBUG
 # define assert(cond) (void) 0
 #else

tests/assert.c

@@ -7,6 +7,7 @@
 int main(void) {
     assert(1 == 1);
     assert(1 + 1 == 2);
+    static_assert(3 == 3);
     puts("yay!");
 
     if (assert(0 == 0), 1) {