Add full compiler toolchain, libc, examples and reference docs

First substantive commit: the entire Sprinter C compiler tree on top of
the bare README+gitignore initial commit.

What's in here:
  bin/sprinter-cc        — driver script invoking SDCC + linker + mkexe
  libc/                  — Sprinter-specific libc layer over ESTEX/BIOS
                           (conio, gfx, io, mem, stdio + headers)
  runtime/               — crt0 variants (default/small/banked/minimal)
                           + heap + bank trampolines
  toolchain/             — mkexe (SprintEXE packer, C + tests)
  examples/              — 30 demo programs (gfx, file I/O, env, time, …)
  lib/Makefile           — builds the libc archive (sprinter.lib)
  docs/                  — converted Sprinter manuals + asm reference samples
  third_party/           — solid-c reference compiler dump + sdcc setup script
  release_docs/          — packaging / release notes

gitignore overhaul:
  • Drop dangerous blanket patterns: *.asm (would hide docs/samples/*.asm)
    and *.exe (case-insensitive match was hiding third_party/solid-c/*.EXE
    on macOS APFS).  Replaced with examples/*/*.{asm,exe,…} and lib/*.lib.
  • Restore tracking of toolchain/mkexe/tests/{one,big}.bin — those are
    INPUT fixtures, not build outputs.
  • Collapse the duplicated SDCC/C/Sdcc sections into one section per
    concern (build outputs / vendored / OS-junk).
  • Add .sprinter-cc-*/, build/ (catches lib/build/ too), .claude/.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

docs/reference/SPRINT2K/SPRN2K55.TXT

@@ -0,0 +1,104 @@
+*** Area: ZX.SPECTRUM                             Date: 18 Jul 37 22:03:37
+*** From: Denis Parinov (2:5030/529.48)
+*** To  : Sergey Krinitsin
+*** Subj: ‚®¯à®á ¯à®¨§¢®¤¨â¥«ï¬ ‘¯¨à¨­â¥à 
+
+        � ¤ ¯à¨¢¥âá⢮¢ âì ⥡ï, Sergey!
+
+   Saturday June 09 2001 Sergey Krinitsin -> Denis Parinov.
+
+ DP>> „ , ï ­¥ ¯p® â®. Ÿ ­¥ ¯p®â¨¢ ªp¨â¨ª¨ ¨ ¤¥«ì­ëå ᮢ¥â®¢, ­®
+ DP>> ¢ ®á­®¢­®¬ ¢áï ªp¨â¨ª  ᢮¤¨âáï ª ¯®¯ë⪠¬ ¢ëáâ ¢¨âì
+ SK> „  ­¥â, ¢á¥ ¥é¥ å㦥... ‘¯¥ªâà㬨áâ ¬ ­¥ ¨¬¥î騬 PC ¢®®¡é¥ ¢ ­ áâ®ï饥
+ SK> ¢à¥¬ï ­  ‘¯à¨­â¥à¥ ¤¥« âì ­¥ç¥£® (¨¬å®).
+ SK>  ‚¥¤ì á®äâ  ¯®¤¤¥à¦¨¢ î饣® à áè¨à¥­­ë¥ ¢®§¬®¦­®á⨠‘¯à¨­â¥à  ã ¢ á
+ SK> ­¥â.
+
+‚® ¯¥p¢ëå ®­ ¥áâì ¨ ¤®áâ â®ç­® ¤ ¢­®. ˆ §¤¥áì ®¡ í⮬ ­¥ p § £®¢®p¨«®áì. ’ë
+¬®£ ¡ë ­ ¯¨á âì çâ® ã ¢ á ¬ «® á®äâ  (çâ® ¡ë«® ¡ë ¯p ¢¤®©), ­® íâ® ­¥ â ª
+ã¡¥¤¨â¥«ì­® §¢ãç¨â.
+
+ SK>  ˆ ᮧ¤ âì ¥£® ­¥ ¨¬¥ï PC ¢¥á쬠 ¯à®¡«¥¬ â¨ç­®.
+
+�⨠¯p®¡«¥¬ë ⮫쪮 ¢ £®«®¢ å, ï p¥èã «î¡ãî § ¤ çã ­¥ ¯p¨¡¥£ ï ª ¯®¬®é¨ PC.
+
+ SK>  Š ª ­ ¯à¨¬¥à à¨á®¢ âì ¯à¨ ¯®¬®é¨ ᯥª®¢áª®£® á®äâ  £à ä¨ªã ¯®¤
+ SK> £à ä¨ç¥áª¨¥ ०¨¬ë ‘¯à¨­â¥à ?
+
+„«ï ­ ç « , ã ­ á ¥áâì £p ä¨ç¥áª¨© p¥¤ ªâ®p.
+ˆ âë ­¥¬­®£® ­¥¤®¯®­¨¬ ¥èì, ª ª ¯p®¨á室¨â ¯p®æ¥áá p §p ¡®âª¨ á®äâ . ƒp ä¨ª 
+®¡ëç­® § ª §ë¢ ¥âìáï å㤮¦­¨ªã/¤¨§ ©­¥pã ¨ ­  祬 ®­ ¥¥ ¡ã¤¥â ¤¥« âì íâ® ¥£®
+¤¥«®. ’ë å®ç¥èì ᪠§ âì çâ® ‘¯p¨­â¥pã ¤ «¥ª® ¤® £p ä¨ç¥áª®© á⠭樨? Ÿ ­¥
+ᯮpî ­¥¬­®£® ¤p㣮© ãp®¢¥­ì, ¤p㣠ï 業 . Ÿ ¢®®¡é¥ ­¥ ¯®­¨¬ î § ç¥¬ ¤®¬ 
+­ã¦­  £p ä¨ç¥áª ï áâ ­æ¨ï? H¥â ï ¯®­¨¬ î, çâ® ­  PC ¥áâì ¨ âãâ ⮦¥ ­ ¤®, ­®
+íâ® ¢á¥ ¯®â®¬ã çâ® ¤®áâ㯥­ ä®â®è®¯ §  $2.
+
+ SK>  ‘ ¦¥«¥§®¬ ¢á¥ ¥é¥ å㦥, §¤¥áì ‘¯à¨­â¥à ¢¥ç­® ¡ã¤¥â § ¢¨á¨âì ®â PC,
+ SK> â.ª. ï ᮬ­¥¢ îáì, çâ® ¢ë ¬®¦¥â¥ § ¨­â¥à¥á®¢ âì €«ìâ¥àã ¢ë¯ãáâ¨âì
+ SK> । ªâ®à ¯®¤ ‘¯à¨­â¥à.
+
+€ § ç¥¬ ⥡¥ ­¥§ ¢¨á¨¬®áâì? Ÿ ­¥ ¯®­¨¬ î, ¬®¦¥â ¥é¥ ¢áî í«¥¬¥­â­ãî ¡ §ã,
+ª®p¯ãá , ¢¨­ç¥áâ¥pë, ¤¨áª®¢®¤ë ⮦¥ ­ ¤® ¤¥« âì ¯p¨ ¯®¬®é¨ ‘¯p¨­â¥p ?
+
+ SK> ’ ª ç⮠ॠ«ì­® ᮧ¤ âì á®äâ ¬®£ãâ «¨è «î¤¨ ¨¬¥î騥 PC.
+
+p¥ «ì­® ¬®¦¥â «î¡®© 祫®¢¥ª. �p®áâ® ¥á«¨ íâ® ¯p®ä¥áᨮ­ «ì­ë© á®äâ â® ¢ ­¥£®
+­ ¤® ¢«®¦¨âì ­¥ ¬ «® ¤¥­¥£. H ¬ ¯p¥¤« £ «¨ ¯®¬®éì ¢ ­ ¯¨á ­¨¨ á®äâ  «î¡®©
+á«®¦­®á⨠¤«ï ‘¯p¨­â¥p . $10000 ¨ £«ã¯ëå ¢®¯p®á®¢ ®­¨ ­¥ § ¤ ¢ «¨.
+
+ SK>  H® áã¤ï ¯® ¨å ®â§ë¢ ¬, ¡®«ì設áâ¢ã ‘¯à¨­â¥à ¬ «®¨­â¥à¥á¥­.
+
+¥é¥ p §, ¨§¤¥«¨¥ ®¤­  èâ㪠, á⮨â á⮫쪮-â®, ¨¬¥¥â á«¥¤ãî騥 å p ªâ¥p¨á⨪¨.
+�â® ¡®«ì設á⢮ ï ¬®£ã ¯¥p¥áç¨â âì ­  ¯ «ìæ å ®¤­®© p㪨. :)
+Ÿ ­¥ ¯®­¨¬ î á¬ëá«  ¢ p¥¯«¨ª å "‚ᥠ¢¨¤¥«¨? Œ­¥ íâ® ­¥ ¨­â¥p¥áâ­®!".
+Š ­ ¬ ¥¦¥¤­¥¢­® ¯p¨å®¤ïâ ¯¨á쬠 ®â «î¤¥© á¯p è¨¢ îé¨å ª®£¤  ­ ç­ãâìáï ¯p®¤ ¦¨
+Sp2000.
+
+ DP>> Š ª¨¥-â® ¡p¥¤®¢ë¥ âp¥¡®¢ ­¨ï, ç⮡ë Sprinter ­¥¯p¥¬¥­­® ¡ë«
+ DP>> ªpãç¥ PC ¨ çâ®¡ë ¬®¦­® ¡ë«® ᮠᯮª®©­®© ᮢ¥áâìî ¯p®¤ âì
+ DP>> PC ¨ ªã¯¨âì Sprinter.
+ SK> —¥«®¢¥ªã ᢮©á⢥­­® áâ६¨âáï ª «ãç襬ã.
+
+ˆ ¤«ï í⮣® ­ ¤® ¯®ªã¯ âì ª®¬¯ìîâ¥p á ¬¥­ì訬¨ å p ªâ¥p¨á⨪ ¬¨? Hã ¬®¦¥â ¨
+â ª p¥ «¨§®¢ ¢ ⥦¥ § ¤ ç¨ ­  ¡®«¥¥ ¤¥è¥¢®¬ ª®¬¯ìîâ¥p¥ ®­ ¯®«ãç¨â ­¥¯«®å®¥
+㤮¢«¥â¢®p¥­¨¥.
+
+ SK>  —â® ­®¢®£® ¯®«ãç â PC'è­¨ª¨ ¯à¨®¡à¥âï ‘¯à¨­â¥à?
+
+ï ¤ã¬ î ®ª®«® $500. …᫨ íâ® ª®­¥ç­®, ­¥ ¤p¥¢­ïï ç¥â¢¥pª  ¨«¨ ¯¥­â¨ã¬.
+
+ SK>  ‚®§¬®¦­®áâì âì á®äâ ‘¯¥ªâà㬠? Ž­¨ ¤ ¢­® ¥£® îâ ¯®¤ í¬ã«ï¬¨.
+
+:) ’ë ¢¨¤¥« —¥p­®£® ‚®p®­  ¨«¨ ‡¢¥§¤­®¥ ­ á«¥¤¨¥ ¨«¨ ¤pã£ãî § é¨é¥­­ãî
+¯p®£p ¬¬ã ¢ í¬ã«ïâ®p¥? € ¢®â ­  ‘¯p¨­â¥p¥ ®­¨ ¯p¥ªp áâ­® p ¡®â îâ. �®«¥¥ ⮣®
+ᮧ¤ ¥âìáï ¢¯¥ç â«¥­¨¥ çâ® ¬­®£¨© á®äâ ¯¨á «áï ¤«ï ‘¯p¨­â¥p ,   ­  ‘¯¥ªâp㬥
+®­ ¯®¤â®p¬ ¦¨¢ ¥â.
+
+ SK> H® çâ® ¯à¨®¡à¥â¥â ॠ«ì騪 ªã¯¨¢è¨© ‘¯à¨­â¥à? Šãçã ­®¢ëå
+ SK> ¢®§¬®¦­®á⥩, ª®â®àë¥ ®­ ᬮ¦¥â ¨á¯®«ì§®¢ âì «¨è ªã¯¨¢ ¢
+ SK> ¤®¡ ¢®ª PC?
+
+H¥â, ®­ ¯®«ãç¨â ᮢp¥¬¥­­ë© ‘¯¥ªâp㬠ᮢ¬¥áâ¨¬ë© ª®¬¯ìîâ¥p. …᫨ á«¥¤®¢ âì
+⢮¥© «®£¨ª¥, â® ¤«ï ⮣® çâ®¡ë ¢®á¯®«ì§®¢ âìáï ¢®§¬®¦­®áâﬨ ‘¯¥ªâp㬠 ⮦¥
+­ã¦­® PC ¯®ªã¯ âì. ‚¥¤ì ¯p¨ ­ ¯¨á ­¨¨ ‘¯¥ªâp㬮¢áª®£® á®äâ  â®¦¥ ç áâ®
+¨á¯®«ì§ã¥âìáï PC.
+
+ SK>  ‡ ç¥¬ ¬­¥, ª ª ॠ«ì騪ã, íâ® ­ ¤®?
+
+„ ¢ © âë ª ª ­¨¡ã¤ì á ¬ ®¯p¥¤¥«¨èìáï, ok?
+
+ SK>>> € ï ¨ ­¥ ¬ãç îáì. Ÿ ¤«ï ¯à®á¬®âà  ä¨«ì¬®¢ î ⥫¥ª +
+ SK>>> H ¨¢ë£®¤­¥©è ï ª®­ä¨£ãà æ¨ï ¯® ᮮ⭮襭¨î 業 /ª ç¥á⢮.
+ DP>> Šáâ â¨ íâ® ¢¥á쬠 p §ã¬­®. Ÿ ¢®â ¯®¤ windows ¯p®£p ¬¬ª¨
+ DP>> ¯¨èã ­  PC,   ­¥ ­  Sprintere.
+ SK> € ª ª ç áâ® âë ¥è PC ¯à¨ ­ ¯¨á ­¨¨ á®äâ  ¯®¤ ‘¯à¨­â¥à?
+
+‘¥©ç á ®ç¥­ì ç áâ®, ¨á室­¨ª¨ ­¥¬¥pï­­®£® ®¡ê¥¬ , ¯p®áâ® ¡ëáâp¥¥ ª®¬¯¨«¨âáï,
+p ­ìè¥ ï ¢®®¡é¥ PC ­¥ ¨á¯®«ì§®¢ «. 2D-Studio, CD-Player, Flex Navigator, Dos
+Commander ¨ ¬­®£®¥ ¤p㣮¥ ¤¥« «®áì ⮫쪮 ­  ‘¯p¨­â¥p¥.
+
+          ‘ 㢠¦¥­¨¥¬, Denis.
+
+... ˆ§ ­ á ç¥â¢¥àëå ¢ í⮩ 娡 à¥ ⮫쪮 ®¤¨­ ˆá ­£ à¤ ¨ ¡ë« 祫®¢¥ª®¬.
+---
+ * Origin: PETERS PLUS LTD (2:5030/529.48)