Add chibicc

This program popped up on Hacker News recently. It's the only modern
compiler I've ever seen that doesn't have dependencies and is easily
modified. So I added all of the missing GNU extensions I like to use
which means it might be possible soon to build on non-Linux and have
third party not vendor gcc binaries.

third_party/chibicc/test/literal_test.c

@@ -0,0 +1,108 @@
+#include "third_party/chibicc/test/test.h"
+
+int main() {
+  ASSERT(97, 'a');
+  ASSERT(10, '\n');
+  ASSERT(-128, '\x80');
+
+  ASSERT(511, 0777);
+  ASSERT(0, 0x0);
+  ASSERT(10, 0xa);
+  ASSERT(10, 0XA);
+  ASSERT(48879, 0xbeef);
+  ASSERT(48879, 0xBEEF);
+  ASSERT(48879, 0XBEEF);
+  ASSERT(0, 0b0);
+  ASSERT(1, 0b1);
+  ASSERT(47, 0b101111);
+  ASSERT(47, 0B101111);
+
+  ASSERT(4, sizeof(0));
+  ASSERT(8, sizeof(0L));
+  ASSERT(8, sizeof(0LU));
+  ASSERT(8, sizeof(0UL));
+  ASSERT(8, sizeof(0LL));
+  ASSERT(8, sizeof(0LLU));
+  ASSERT(8, sizeof(0Ull));
+  ASSERT(8, sizeof(0l));
+  ASSERT(8, sizeof(0ll));
+  ASSERT(8, sizeof(0x0L));
+  ASSERT(8, sizeof(0b0L));
+  ASSERT(4, sizeof(2147483647));
+  ASSERT(8, sizeof(2147483648));
+  ASSERT(-1, 0xffffffffffffffff);
+  ASSERT(8, sizeof(0xffffffffffffffff));
+  ASSERT(4, sizeof(4294967295U));
+  ASSERT(8, sizeof(4294967296U));
+
+  ASSERT(3, -1U >> 30);
+  ASSERT(3, -1Ul >> 62);
+  ASSERT(3, -1ull >> 62);
+
+  ASSERT(1, 0xffffffffffffffffl >> 63);
+  ASSERT(1, 0xffffffffffffffffll >> 63);
+
+  ASSERT(-1, 18446744073709551615);
+  ASSERT(8, sizeof(18446744073709551615));
+  ASSERT(-1, 18446744073709551615 >> 63);
+
+  ASSERT(-1, 0xffffffffffffffff);
+  ASSERT(8, sizeof(0xffffffffffffffff));
+  ASSERT(1, 0xffffffffffffffff >> 63);
+
+  ASSERT(-1, 01777777777777777777777);
+  ASSERT(8, sizeof(01777777777777777777777));
+  ASSERT(1, 01777777777777777777777 >> 63);
+
+  ASSERT(-1,
+         0b1111111111111111111111111111111111111111111111111111111111111111);
+  ASSERT(
+      8,
+      sizeof(
+          0b1111111111111111111111111111111111111111111111111111111111111111));
+  ASSERT(
+      1,
+      0b1111111111111111111111111111111111111111111111111111111111111111 >> 63);
+
+  ASSERT(8, sizeof(2147483648));
+  ASSERT(4, sizeof(2147483647));
+
+  ASSERT(8, sizeof(0x1ffffffff));
+  ASSERT(4, sizeof(0xffffffff));
+  ASSERT(1, 0xffffffff >> 31);
+
+  ASSERT(8, sizeof(040000000000));
+  ASSERT(4, sizeof(037777777777));
+  ASSERT(1, 037777777777 >> 31);
+
+  ASSERT(8, sizeof(0b111111111111111111111111111111111));
+  ASSERT(4, sizeof(0b11111111111111111111111111111111));
+  ASSERT(1, 0b11111111111111111111111111111111 >> 31);
+
+  ASSERT(-1, 1 << 31 >> 31);
+  ASSERT(-1, 01 << 31 >> 31);
+  ASSERT(-1, 0x1 << 31 >> 31);
+  ASSERT(-1, 0b1 << 31 >> 31);
+
+  0.0;
+  1.0;
+  3e+8;
+  0x10.1p0;
+  .1E4f;
+
+  ASSERT(4, sizeof(8f));
+  ASSERT(4, sizeof(0.3F));
+  ASSERT(8, sizeof(0.));
+  ASSERT(8, sizeof(.0));
+  ASSERT(16, sizeof(5.l));
+  ASSERT(16, sizeof(2.0L));
+
+  Assert(1, size\
+of(char),
+         "sizeof(char)");
+
+  ASSERT(4, sizeof(L'\0'));
+  ASSERT(97, L'a');
+
+  return 0;
+}