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.

libc/conv/conv.h

@@ -97,7 +97,7 @@ double RoundDecimalPlaces(double, double, double (*)(double));
 #endif
 
 #ifndef __STRICT_ANSI__
-intmax_t __imaxabs(intmax_t) asm("imaxabs") libcesque pureconst;
+intmax_t __imaxabs(intmax_t) libcesque pureconst;
 #define imaxabs(x) __imaxabs(x)
 #endif /* !ANSI */
 

libc/conv/imaxabs.c

@@ -20,6 +20,6 @@
 #include "libc/conv/conv.h"
 #include "libc/macros.h"
 
-intmax_t imaxabs(intmax_t x) {
+intmax_t(imaxabs)(intmax_t x) {
   return ABS(x);
 }

libc/conv/imaxabs.thunk.S

@@ -0,0 +1,24 @@
+/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8     -*-│
+│vi: set et ft=asm ts=8 tw=8 fenc=utf-8                                     :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ This program is free software; you can redistribute it and/or modify         │
+│ it under the terms of the GNU General Public License as published by         │
+│ the Free Software Foundation; version 2 of the License.                      │
+│                                                                              │
+│ This program is distributed in the hope that it will be useful, but          │
+│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
+│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
+│ General Public License for more details.                                     │
+│                                                                              │
+│ You should have received a copy of the GNU General Public License            │
+│ along with this program; if not, write to the Free Software                  │
+│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
+│ 02110-1301 USA                                                               │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/macros.h"
+
+__imaxabs:
+	jmp	imaxabs
+	.endfn	__imaxabs,globl

libc/conv/strtoimax.c

@@ -37,10 +37,10 @@
  * @see strtoumax
  */
 intmax_t strtoimax(const char *s, char **endptr, int base) {
+  bool neg;
   uintmax_t x;
   intmax_t res;
   unsigned diglet, bits;
-  bool neg, islong, isunsigned;
 
   x = 0;
   bits = 0;
@@ -104,8 +104,6 @@ intmax_t strtoimax(const char *s, char **endptr, int base) {
     }
   }
 
-  if ((isunsigned = *s == 'u' || *s == 'U')) s++;
-  if ((islong = *s == 'l' || *s == 'L')) s++;
   if (endptr) *endptr = s;
 
   if (neg) {
@@ -114,13 +112,5 @@ intmax_t strtoimax(const char *s, char **endptr, int base) {
     res = x;
   }
 
-  if (isunsigned) {
-    if (islong) {
-      res = (uint64_t)res;
-    } else {
-      res = (uint32_t)res;
-    }
-  }
-
   return res;
 }