Add curl example (#42)

make -j8 o//examples/curl.com
    o//examples/curl.com http://justine.lol/ape.html

libc/dns/dns.h

@@ -1,15 +1,34 @@
 #ifndef COSMOPOLITAN_LIBC_DNS_DNS_H_
 #define COSMOPOLITAN_LIBC_DNS_DNS_H_
-#if !(__ASSEMBLER__ + __LINKER__ + 0)
-COSMOPOLITAN_C_START_
+#include "libc/dns/resolvconf.h"
+#include "libc/sock/sock.h"
 
-#define DNS_PORT 53
-#define DNS_NAME_MAX 253
+#define DNS_PORT      53
+#define DNS_NAME_MAX  253
 #define DNS_LABEL_MAX 63
 
-struct sockaddr;
-struct sockaddr_in;
-struct ResolvConf;
+#define EAI_SUCCESS     0
+#define EAI_BADFLAGS    -1
+#define EAI_NONAME      -2
+#define EAI_AGAIN       -3
+#define EAI_FAIL        -4
+#define EAI_NODATA      -5
+#define EAI_FAMILY      -6
+#define EAI_SOCKTYPE    -7
+#define EAI_SERVICE     -8
+#define EAI_ADDRFAMILY  -9
+#define EAI_MEMORY      -10
+#define EAI_OVERFLOW    -12
+#define EAI_SYSTEM      -11
+#define EAI_ALLDONE     -103
+#define EAI_CANCELED    -101
+#define EAI_IDN_ENCODE  -105
+#define EAI_INPROGRESS  -100
+#define EAI_INTR        -104
+#define EAI_NOTCANCELED -102
+
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
 
 struct addrinfo {
   int32_t ai_flags;    /* AI_XXX */

libc/dns/eai2str.c

@@ -17,30 +17,51 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/dns/dns.h"
-#include "libc/sysv/consts/eai.h"
 
 /**
  * Turns getaddrinfo() return code into string.
  */
 const char *eai2str(int code) {
-  if (code == EAI_ADDRFAMILY) return "ADDRFAMILY";
-  if (code == EAI_AGAIN) return "AGAIN";
-  if (code == EAI_ALLDONE) return "ALLDONE";
-  if (code == EAI_BADFLAGS) return "BADFLAGS";
-  if (code == EAI_CANCELED) return "CANCELED";
-  if (code == EAI_FAIL) return "FAIL";
-  if (code == EAI_FAMILY) return "FAMILY";
-  if (code == EAI_IDN_ENCODE) return "ENCODE";
-  if (code == EAI_INPROGRESS) return "INPROGRESS";
-  if (code == EAI_INTR) return "INTR";
-  if (code == EAI_MEMORY) return "MEMORY";
-  if (code == EAI_NODATA) return "NODATA";
-  if (code == EAI_NONAME) return "NONAME";
-  if (code == EAI_NOTCANCELED) return "NOTCANCELED";
-  if (code == EAI_OVERFLOW) return "OVERFLOW";
-  if (code == EAI_SERVICE) return "SERVICE";
-  if (code == EAI_SOCKTYPE) return "SOCKTYPE";
-  if (code == EAI_SUCCESS) return "SUCCESS";
-  if (code == EAI_SYSTEM) return "SYSTEM";
-  return "???";
+  switch (code) {
+    case EAI_ADDRFAMILY:
+      return "ADDRFAMILY";
+    case EAI_AGAIN:
+      return "AGAIN";
+    case EAI_ALLDONE:
+      return "ALLDONE";
+    case EAI_BADFLAGS:
+      return "BADFLAGS";
+    case EAI_CANCELED:
+      return "CANCELED";
+    case EAI_FAIL:
+      return "FAIL";
+    case EAI_FAMILY:
+      return "FAMILY";
+    case EAI_IDN_ENCODE:
+      return "ENCODE";
+    case EAI_INPROGRESS:
+      return "INPROGRESS";
+    case EAI_INTR:
+      return "INTR";
+    case EAI_MEMORY:
+      return "MEMORY";
+    case EAI_NODATA:
+      return "NODATA";
+    case EAI_NONAME:
+      return "NONAME";
+    case EAI_NOTCANCELED:
+      return "NOTCANCELED";
+    case EAI_OVERFLOW:
+      return "OVERFLOW";
+    case EAI_SERVICE:
+      return "SERVICE";
+    case EAI_SOCKTYPE:
+      return "SOCKTYPE";
+    case EAI_SUCCESS:
+      return "SUCCESS";
+    case EAI_SYSTEM:
+      return "SYSTEM";
+    default:
+      return "???";
+  }
 }

libc/dns/getaddrinfo.c

@@ -27,7 +27,6 @@
 #include "libc/str/str.h"
 #include "libc/sysv/consts/af.h"
 #include "libc/sysv/consts/ai.h"
-#include "libc/sysv/consts/eai.h"
 #include "libc/sysv/consts/inaddr.h"
 #include "libc/sysv/errfuns.h"
 

libc/dns/resolvconf.h

@@ -1,11 +1,10 @@
 #ifndef COSMOPOLITAN_LIBC_DNS_RESOLVCONF_H_
 #define COSMOPOLITAN_LIBC_DNS_RESOLVCONF_H_
+#include "libc/sock/sock.h"
+#include "libc/stdio/stdio.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
-struct FILE;
-struct sockaddr_in;
-
 struct Nameservers {
   size_t i, n;
   struct sockaddr_in *p;