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/str/memccpy.c

@@ -19,13 +19,6 @@
 #include "libc/bits/bits.h"
 #include "libc/str/str.h"
 
-static inline noasan uint64_t UncheckedAlignedRead64(unsigned char *p) {
-  return (uint64_t)(255 & p[7]) << 070 | (uint64_t)(255 & p[6]) << 060 |
-         (uint64_t)(255 & p[5]) << 050 | (uint64_t)(255 & p[4]) << 040 |
-         (uint64_t)(255 & p[3]) << 030 | (uint64_t)(255 & p[2]) << 020 |
-         (uint64_t)(255 & p[1]) << 010 | (uint64_t)(255 & p[0]) << 000;
-}
-
 /**
  * Copies at most N bytes from SRC to DST until 𝑐 is encountered.
  *