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

libc/type2str.h

@@ -0,0 +1,44 @@
+#ifndef COSMOPOLITAN_LIBC_TYPE2STR_H_
+#define COSMOPOLITAN_LIBC_TYPE2STR_H_
+#if __STDC_VERSION__ + 0 >= 201112
+/* clang-format off */
+
+#define _TYPE2STR(X)                          \
+  _Generic(X,                                 \
+    _Bool:              "_Bool",              \
+    signed char:        "signed char",        \
+    unsigned char:      "unsigned char",      \
+    char:               "char",               \
+    short:              "short",              \
+    unsigned short:     "unsigned short",     \
+    int:                "int",                \
+    unsigned:           "unsigned",           \
+    long:               "long",               \
+    unsigned long:      "unsigned long",      \
+    long long:          "long long",          \
+    unsigned long long: "unsigned long long", \
+    float:              "float",              \
+    double:             "double",             \
+    long double:        "long double")
+
+#define _PRINTF_GENERIC(X, D, U) \
+  _Generic(X,                    \
+    _Bool:              "hhh" U, \
+    signed char:        "hh" D,  \
+    unsigned char:      "hh" U,  \
+    char:               "hh" D,  \
+    short:              "h" D,   \
+    unsigned short:     "h" U,   \
+    int:                D,       \
+    unsigned:           U,       \
+    long:               "l" D,   \
+    unsigned long:      "l" U,   \
+    long long:          "ll" D,  \
+    unsigned long long: "ll" U,  \
+    float:              "f",     \
+    double:             "f",     \
+    long double:        "Lf")
+
+/* clang-format on */
+#endif /* C11 */
+#endif /* COSMOPOLITAN_LIBC_TYPE2STR_H_ */