Make improvements

- Improved async signal safety of read() particularly for longjmp()
- Started adding cancel cleanup handlers for locks / etc on Windows
- Make /dev/tty work better particularly for uses like `foo | less`
- Eagerly read console input into a linked list, so poll can signal
- Fix some libc definitional bugs, which configure scripts detected

test/libc/runtime/getdosargv_test.c

@@ -25,11 +25,6 @@
 #include "libc/testlib/testlib.h"
 
 void SetUpOnce(void) {
-  if (!IsWindows()) {
-    // TODO(jart): mock out that win32 i/o call
-    tinyprint(2, program_invocation_name, ": skipping on non-windows\n", NULL);
-    exit(0);
-  }
   testlib_enable_tmp_setup_teardown();
 }
 
@@ -197,16 +192,3 @@ TEST(GetDosArgv, cmdToil) {
   free(argv);
   free(buf);
 }
-
-TEST(GetDosArgv, canonicalizesCurrentDirectoryCommandPath) {
-  size_t max = 4;
-  size_t size = ARG_MAX / 2;
-  char *buf = malloc(size * sizeof(char));
-  char **argv = malloc(max * sizeof(char *));
-  ASSERT_SYS(0, 0, touch("emacs.com", 0755));
-  EXPECT_EQ(1, GetDosArgv(u"emacs.com", buf, size, argv, max));
-  EXPECT_STREQ(".\\emacs.com", argv[0]);
-  EXPECT_EQ(NULL, argv[1]);
-  free(argv);
-  free(buf);
-}