file(1): add ogg, TrueType font, LLVM bitcode, PEM certs, and PE executables.

More of the files encountered on the Android system image (plus PE
executables, which we build but which shouldn't actually make it to the
system image!).
diff --git a/toys/posix/file.c b/toys/posix/file.c
index 2f1e95b..5e5c15b 100644
--- a/toys/posix/file.c
+++ b/toys/posix/file.c
@@ -270,6 +270,49 @@
     else what = NULL;
     if (what) xprintf("%s\n", what);
     else xprintf("(bad type %d)\n", s[9]);
+  } else if (len>36 && !memcmp(s, "OggS\x00\x02", 6)) {
+    xprintf("Ogg data");
+    // https://wiki.xiph.org/MIMETypesCodecs
+    if (!memcmp(s+28, "CELT    ", 8)) xprintf(", celt audio");
+    if (!memcmp(s+28, "CMML    ", 8)) xprintf(", cmml text");
+    if (!memcmp(s+28, "BBCD\0", 5)) xprintf(", dirac video");
+    if (!memcmp(s+28, "\177FLAC", 5)) xprintf(", flac audio");
+    if (!memcmp(s+28, "\x8bJNG\r\n\x1a\n", 8)) xprintf(", jng video");
+    if (!memcmp(s+28, "\x80kate\0\0\0", 8)) xprintf(", kate text");
+    if (!memcmp(s+28, "OggMIDI\0", 8)) xprintf(", midi text");
+    if (!memcmp(s+28, "\x8aMNG\r\n\x1a\n", 8)) xprintf(", mng video");
+    if (!memcmp(s+28, "OpusHead", 8)) xprintf(", opus audio");
+    if (!memcmp(s+28, "PCM     ", 8)) xprintf(", pcm audio");
+    if (!memcmp(s+28, "\x89PNG\r\n\x1a\n", 8)) xprintf(", png video");
+    if (!memcmp(s+28, "Speex   ", 8)) xprintf(", speex audio");
+    if (!memcmp(s+28, "\x80theora", 7)) xprintf(", theora video");
+    if (!memcmp(s+28, "\x01vorbis", 7)) xprintf(", vorbis audio");
+    if (!memcmp(s+28, "YUV4MPEG", 8)) xprintf(", yuv4mpeg video");
+    xputc('\n');
+  } else if (len>12 && !memcmp(s, "\x00\x01\x00\x00", 4)) {
+    xputs("TrueType font");
+  } else if (len>12 && !memcmp(s, "ttcf\x00", 5)) {
+    xprintf("TrueType font collection, version %d, %d fonts\n",
+            (int)peek_be(s+4, 2), (int)peek_be(s+8, 4));
+  } else if (len>4 && !memcmp(s, "BC\xc0\xde", 4)) {
+    xputs("LLVM IR bitcode");
+  } else if (strstart(&s, "-----BEGIN CERTIFICATE-----")) {
+    xputs("PEM certificate");
+
+  // https://msdn.microsoft.com/en-us/library/windows/desktop/ms680547(v=vs.85).aspx
+  } else if (len>0x70 && !memcmp(s, "MZ", 2) &&
+      (magic=peek_le(s+0x3c,4))<len-4 && !memcmp(s+magic, "\x50\x45\0\0", 4)) {
+    xprintf("MS PE32%s executable %s", (peek_le(s+magic+24, 2)==0x20b)?"+":"",
+        (peek_le(s+magic+22, 2)&0x2000)?"(DLL) ":"");
+    if (peek_le(s+magic+20, 2)>70) {
+      char *types[] = {0, "native", "GUI", "console", "OS/2", "driver", "CE",
+          "EFI", "EFI boot", "EFI runtime", "EFI ROM", "XBOX", 0, "boot"};
+      int type = peek_le(s+magic+92, 2);
+      char *name = (type>0 && type<ARRAY_LEN(types))?types[type]:0;
+
+      xprintf("(%s) ", name?name:"unknown");
+    }
+    xprintf("%s\n", (peek_le(s+magic+4, 2)==0x14c)?"x86":"x86-64");
   } else {
     char *what = 0;
     int i, bytes;