Write tests for new APE loader and fix bugs

- Add FreeBSD-specific mmap() flags
- Reduce size of the APE loader from 8kb to 4kb
- Work towards fixing the Makefile build on WSL
- Automate testing of APE no-modify-self behaviors
- Make the ape.S shell script code cleaner and tinier
- Improve the APE sanity check to test behavior better
- Fixed issue with ShowCrashReports() sigaltstack() on BSDs
- Delete symbols for S_MODE magnums which wasted compile time

If you checked out yesterday's APE commit, please run:

    rm -f /usr/bin/ape o/tmp/ape /tmp/ape "${TMPDIR:-/tmp}/ape"

Because this change fixes certain aspects of the new ABI. We don't have
automated migrations for APE loader versions yet. Thanks! You can also
download prebuilt binaries here:

- https://justine.lol/ape.elf    (Linux/FreeBSD/NetBSD/OpenBSD)
- https://justine.lol/ape.macho  (Apple)

Install the appropriate one as `/usr/bin/ape`.

libc/calls/write-nt.c

@@ -16,10 +16,15 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/bits/weaken.h"
 #include "libc/calls/internal.h"
 #include "libc/calls/sig.internal.h"
+#include "libc/calls/strace.internal.h"
+#include "libc/errno.h"
 #include "libc/nt/errors.h"
 #include "libc/nt/runtime.h"
+#include "libc/runtime/internal.h"
+#include "libc/runtime/runtime.h"
 #include "libc/sysv/consts/sicode.h"
 #include "libc/sysv/consts/sig.h"
 #include "libc/sysv/errfuns.h"
@@ -37,12 +42,18 @@ static textwindows ssize_t sys_write_nt_impl(int fd, void *data, size_t size,
     //   return ebadf(); /* handled by consts.sh */
     // case kNtErrorNotEnoughQuota:
     //   return edquot(); /* handled by consts.sh */
-    case kNtErrorBrokenPipe:            // broken pipe
-    case kNtErrorNoData:                // closing named pipe
-      __sig_raise(SIGPIPE, SI_KERNEL);  //
-      return epipe();                   //
-    case kNtErrorAccessDenied:          // write doesn't return EACCESS
-      return ebadf();                   //
+    case kNtErrorBrokenPipe:  // broken pipe
+    case kNtErrorNoData:      // closing named pipe
+      if (weaken(__sig_raise)) {
+        weaken(__sig_raise)(SIGPIPE, SI_KERNEL);
+        return epipe();
+      } else {
+        STRACE("broken pipe");
+        __restorewintty();
+        _Exit(128 + EPIPE);
+      }
+    case kNtErrorAccessDenied:  // write doesn't return EACCESS
+      return ebadf();           //
     default:
       return __winerr();
   }