Refactor some code

- Write tests for cthreads
- Fix bugs in pe2.com tool
- Fix ASAN issue with GetDosEnviron()
- Consolidate the cthread header files
- Some code size optimizations for MODE=
- Attempted to squash a tls linker warning
- Attempted to get futexes working on FreeBSD

libc/thread/freebsd.internal.h

@@ -3,8 +3,6 @@
 #include "libc/bits/asmflag.h"
 #include "libc/calls/struct/timespec.h"
 #include "libc/errno.h"
-#if !(__ASSEMBLER__ + __LINKER__ + 0)
-COSMOPOLITAN_C_START_
 
 /**
  * @fileoverview FreeBSD Threading
@@ -13,6 +11,13 @@ COSMOPOLITAN_C_START_
  *     maximum legal range is PID_MAX + 2 (100001) through INT_MAX
  */
 
+#define UMTX_OP_MUTEX_WAIT 17
+#define UMTX_OP_MUTEX_WAKE 18
+#define UMTX_ABSTIME       1
+
+#if !(__ASSEMBLER__ + __LINKER__ + 0)
+COSMOPOLITAN_C_START_
+
 struct rtprio {
   uint16_t type; /* scheduling class */
   uint16_t prio;
@@ -31,6 +36,14 @@ struct thr_param {
   struct rtprio *rtp;
 };
 
+struct _umtx_time {
+  struct timespec _timeout;
+  uint32_t _flags;
+  uint32_t _clockid;
+};
+
+int _umtx_op(void *, int, unsigned long, void *, void *);
+
 COSMOPOLITAN_C_END_
 #endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_LIBC_THREAD_FREEBSD_INTERNAL_H_ */