Improve synchronization

- Fix bugs in kDos2Errno definition
- malloc() should now be thread safe
- Fix bug in rollup.com header generator
- Fix open(O_APPEND) on the New Technology
- Fix select() on the New Technology and test it
- Work towards refactoring i/o for thread safety
- Socket reads and writes on NT now poll for signals
- Work towards i/o completion ports on the New Technology
- Make read() and write() intermittently check for signals
- Blinkenlights keyboard i/o so much better on NT w/ poll()
- You can now poll() files and sockets at the same time on NT
- Fix bug in appendr() that manifests with dlmalloc footers off

third_party/dlmalloc/vespene.internal.h

@@ -0,0 +1,10 @@
+#ifndef COSMOPOLITAN_THIRD_PARTY_DLMALLOC_VESPENE_INTERNAL_H_
+#define COSMOPOLITAN_THIRD_PARTY_DLMALLOC_VESPENE_INTERNAL_H_
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
+void *dlmalloc_requires_more_vespene_gas(size_t);
+
+COSMOPOLITAN_C_END_
+#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
+#endif /* COSMOPOLITAN_THIRD_PARTY_DLMALLOC_VESPENE_INTERNAL_H_ */