Fix .wolfssl_known_macro_extras ordering and add __unix__

Sort was failing because IN_CLOEXEC and O_CLOEXEC were placed before
sibling names where '_' sorts after uppercase letters in LC_ALL=C
order. Move them into the correct positions and register __unix__,
which is now referenced by the new cloexec wrapper guards.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: embhorn

.wolfssl_known_macro_extras

@@ -317,9 +317,9 @@ ID_TRNG
 IGNORE_KEY_EXTENSIONS
 IGNORE_NETSCAPE_CERT_TYPE
 INCLUDE_uxTaskGetStackHighWaterMark
-IN_CLOEXEC
 INTEGRITY
 INTIMEVER
+IN_CLOEXEC
 IOTSAFE_NO_GETDATA
 IOTSAFE_SIG_8BIT_LENGTH
 KCAPI_USE_XMALLOC
@@ -471,7 +471,6 @@ NO_WOLFSSL_XILINX_TAG_MALLOC
 NRF52
 NRF52_SERIES
 NRF_ERROR_MODULE_ALREADY_INITIALIZED
-O_CLOEXEC
 OLD_HELLO_ALLOWED
 OPENSSL_EXTRA_BSD
 OPENSSL_EXTRA_NO_ASN1
@@ -480,6 +479,7 @@ OPENSSL_NO_PK
 OS_WINDOWS
 OTHERBOARD
 OTHER_BOARD
+O_CLOEXEC
 PEER_INFO
 PERF_FLAG_FD_CLOEXEC
 PKA_ECC_SCALAR_MUL_IN_B_COEFF
@@ -1122,6 +1122,7 @@ __sun
 __svr4__
 __thumb__
 __ti__
+__unix__
 __x86_64__
 __xtensa__
 byte