Rewrite .zip.o file linker

This change takes an entirely new approach to the incremental linking of
pkzip executables. The assets created by zipobj.com are now treated like
debug data. After a .com.dbg is compiled, fixupobj.com should be run, so
it can apply fixups to the offsets and move the zip directory to the end
of the file. Since debug data doesn't get objcopy'd, a new tool has been
introduced called zipcopy.com which should be run after objcopy whenever
a .com file is created. This is all automated by the `cosmocc` toolchain
which is rapidly becoming the new recommended approach.

This change also introduces the new C23 checked arithmetic macros.

tool/build/zipobj.c

@@ -47,25 +47,46 @@ char *symbol_;
 char *outpath_;
 bool nocompress_;
 bool basenamify_;
-int64_t image_base_;
 int strip_components_;
 const char *path_prefix_;
 struct timespec timestamp;
-size_t kZipCdirHdrLinkableSizeBootstrap;
 
 wontreturn void PrintUsage(int rc) {
-  kprintf("%s%s%s\n", "Usage: ", program_invocation_name,
-          " [-n] [-B] [-C INT] [-P PREFIX] [-o FILE] [-s SYMBOL] [-y YOINK] "
-          "[FILE...]");
+  kprintf("\n\
+NAME\n\
+\n\
+  Cosmpolitan Zip File Compiler\n\
+\n\
+SYNOPSIS\n\
+\n\
+  %s [FLAGS] FILE...\n\
+\n\
+DESCRIPTION\n\
+\n\
+  This program may be used to turn arbitrary files into .zip.o files\n\
+  which can be incrementally linked into binaries, without quadratic\n\
+  compression complexity.\n\
+\n\
+FLAGS\n\
+\n\
+  -h              show help\n\
+  -o PATH         output path\n\
+  -0              disable compression\n\
+  -B              basename-ify zip filename\n\
+  -N ZIPPATH      zip filename (defaults to input arg)\n\
+  -P ZIPPATH      prepend path zip filename using join\n\
+  -C INTEGER      strips leading path components from zip filename\n\
+  -y SYMBOL       generate yoink for symbol (default __zip_eocd)\n\
+\n\
+",
+          program_invocation_name);
   exit(rc);
 }
 
 void GetOpts(int *argc, char ***argv) {
   int opt;
-  yoink_ = "__zip_start";
-  image_base_ = IMAGE_BASE_VIRTUAL;
-  kZipCdirHdrLinkableSizeBootstrap = kZipCdirHdrLinkableSize;
-  while ((opt = getopt(*argc, *argv, "?0nhBL:N:C:P:o:s:y:b:")) != -1) {
+  yoink_ = "__zip_eocd";
+  while ((opt = getopt(*argc, *argv, "?0nhBN:C:P:o:s:y:")) != -1) {
     switch (opt) {
       case 'o':
         outpath_ = optarg;
@@ -90,15 +111,9 @@ void GetOpts(int *argc, char ***argv) {
       case 'B':
         basenamify_ = true;
         break;
-      case 'b':
-        image_base_ = strtol(optarg, NULL, 0);
-        break;
       case '0':
         nocompress_ = true;
         break;
-      case 'L':
-        kZipCdirHdrLinkableSizeBootstrap = strtoul(optarg, NULL, 0);
-        break;
       case '?':
       case 'h':
         PrintUsage(EXIT_SUCCESS);
@@ -108,7 +123,12 @@ void GetOpts(int *argc, char ***argv) {
   }
   *argc -= optind;
   *argv += optind;
-  CHECK_NOTNULL(outpath_);
+  if (!outpath_) {
+    kprintf("error: no output path specified\n"
+            "run %s -h for usage\n",
+            program_invocation_name);
+    exit(1);
+  }
 }
 
 void ProcessFile(struct ElfWriter *elf, const char *path) {
@@ -143,23 +163,20 @@ void ProcessFile(struct ElfWriter *elf, const char *path) {
     }
   }
   elfwriter_zip(elf, name, name, strlen(name), map, st.st_size, st.st_mode,
-                timestamp, timestamp, timestamp, nocompress_, image_base_,
-                kZipCdirHdrLinkableSizeBootstrap);
+                timestamp, timestamp, timestamp, nocompress_);
   if (st.st_size) CHECK_NE(-1, munmap(map, st.st_size));
   close(fd);
 }
 
 void PullEndOfCentralDirectoryIntoLinkage(struct ElfWriter *elf) {
   elfwriter_align(elf, 1, 0);
-  elfwriter_startsection(elf, ".yoink", SHT_PROGBITS,
-                         SHF_ALLOC | SHF_EXECINSTR);
+  elfwriter_startsection(elf, ".yoink", SHT_PROGBITS, SHF_EXECINSTR);
   elfwriter_yoink(elf, yoink_, STB_GLOBAL);
   elfwriter_finishsection(elf);
 }
 
 void CheckFilenameKosher(const char *path) {
-  CHECK_LE(kZipCfileHdrMinSize + strlen(path),
-           kZipCdirHdrLinkableSizeBootstrap);
+  CHECK_LE(kZipCfileHdrMinSize + strlen(path), 65535);
   CHECK(!_startswith(path, "/"));
   CHECK(!strstr(path, ".."));
 }