tidy-up: delete unused build configuration macros

Most of them feature guards:

- `CURL_INCLUDES_SYS_UIO` [1]
- `HAVE_ALLOCA_H` [2]
- `HAVE_CRYPTO_CLEANUP_ALL_EX_DATA` (unused since de71e68000c8624ea13f90b136f8734dd0fb1bdc)
- `HAVE_DLFCN_H`
- `HAVE_DLOPEN`
- `HAVE_DOPRNT`
- `HAVE_FCNTL`
- `HAVE_GETHOSTBYNAME` [3]
- `HAVE_GETOPT_H`
- `HAVE_GETPASS`
- `HAVE_GETPROTOBYNAME`
- `HAVE_GETSERVBYNAME`
- `HAVE_IDN_FREE*`
- `HAVE_INET_ADDR`
- `HAVE_IOCTL`
- `HAVE_KRB4`
- `HAVE_KRB_GET_OUR_IP_FOR_REALM`
- `HAVE_KRB_H`
- `HAVE_LDAPSSL_H`
- `HAVE_LDAP_INIT_FD`
- `HAVE_LIBDL`
- `HAVE_LIBNSL`
- `HAVE_LIBRESOLV*`
- `HAVE_LIBUCB`
- `HAVE_LL`
- `HAVE_LOCALTIME_R`
- `HAVE_MALLOC_H`
- `HAVE_MEMCPY`
- `HAVE_MEMORY_H`
- `HAVE_NETINET_IF_ETHER_H`
- `HAVE_NI_WITHSCOPEID`
- `HAVE_OPENSSL_CRYPTO_H`
- `HAVE_OPENSSL_ERR_H`
- `HAVE_OPENSSL_PEM_H`
- `HAVE_OPENSSL_PKCS12_H`
- `HAVE_OPENSSL_RAND_H`
- `HAVE_OPENSSL_RSA_H`
- `HAVE_OPENSSL_SSL_H`
- `HAVE_OPENSSL_X509_H`
- `HAVE_PEM_H`
- `HAVE_POLL`
- `HAVE_RAND_SCREEN`
- `HAVE_RAND_STATUS`
- `HAVE_RECVFROM`
- `HAVE_SETSOCKOPT`
- `HAVE_SETVBUF`
- `HAVE_SIZEOF_LONG_DOUBLE`
- `HAVE_SOCKIO_H`
- `HAVE_SOCK_OPTS`
- `HAVE_STDIO_H`
- `HAVE_STRCASESTR`
- `HAVE_STRFTIME`
- `HAVE_STRLCAT`
- `HAVE_STRNCMPI`
- `HAVE_STRNICMP`
- `HAVE_STRSTR`
- `HAVE_STRUCT_IN6_ADDR`
- `HAVE_TLD_H`
- `HAVE_TLD_STRERROR`
- `HAVE_UNAME`
- `HAVE_USLEEP`
- `HAVE_WINBER_H`
- `HAVE_WRITEV`
- `HAVE_X509_H`
- `LT_OBJDIR`
- `NEED_BASENAME_PROTO`
- `NOT_NEED_LIBNSL`
- `OPENSSL_NO_KRB5`
- `RECVFROM_TYPE*`
- `SIZEOF_LONG_DOUBLE`
- `STRERROR_R_TYPE_ARG3`
- `USE_YASSLEMUL`
- `_USRDLL` (from CMake) [4]

[1] Related parts in `m4/curl-functions.m4` and `configure.ac` might
    also be deleted.

[2] Related comment can possibly be deleted in
    `packages/vms/generate_config_vms_h_curl.com`.

[3] There are more instances of this in autotools, but I did not dare to
    touch those. Looked like it's used to detect socket support.

[4] This is necessary for MFC (Microsoft Foundation Class) DLLs to
    force linking MFC components statically to the DLL. `libcurl.dll`
    does not use MFC, so we can delete this define.
    Ref: https://docs.microsoft.com/cpp/build/regular-dlls-statically-linked-to-mfc

Script that can help finding unused settings like above:
```shell

autoheader configure.ac  # generate lib/curl_config.h.in

{
  grep -o -E    'set\([A-Z][A-Z0-9_]{3,}'          CMake/Platforms/WindowsCache.cmake | sed -E 's|set\(||g'
  grep -o -E -h '#define +[A-Z][A-Z0-9_]{3,}'      lib/config-*.h                     | sed -E 's|#define +||g'
  grep -o -E    '#cmakedefine +[A-Z][A-Z0-9_]{3,}' lib/curl_config.h.cmake            | sed -E 's|#cmakedefine +||g'
  grep -o -E    '#undef +[A-Z][A-Z0-9_]{3,}'       lib/curl_config.h.in               | sed -E 's|#undef +||g'
} | sort -u | grep -v -F 'HEADER_CURL_' | while read -r def; do
  c="$(git grep -w -F "${def}" | grep -v -E -c '(/libcurl\.tmpl|^lib/config-|^lib/curl_config\.h\.cmake|^CMakeLists\.txt|^CMake/Platforms/WindowsCache\.cmake|^packages/vms/config_h\.com|^m4/curl-functions\.m4|^acinclude\.m4|^configure\.ac)')"
  if [ "${c}" = '0' ]; then
    echo "${def}"
  fi
done
```

Reviewed-by: Daniel Stenberg
Closes #9044

1 files changed, 0 insertions, 40 deletions

diff --git a/lib/curl_setup_once.h b/lib/curl_setup_once.h
index 656dc0837..e9730c928 100644
--- a/lib/curl_setup_once.h
+++ b/lib/curl_setup_once.h
@@ -204,46 +204,6 @@ struct timeval {
 #endif /* HAVE_SEND */
 
 
-#if 0
-#if defined(HAVE_RECVFROM)
-/*
- * Currently recvfrom is only used on udp sockets.
- */
-#if !defined(RECVFROM_TYPE_ARG1) || \
-    !defined(RECVFROM_TYPE_ARG2) || \
-    !defined(RECVFROM_TYPE_ARG3) || \
-    !defined(RECVFROM_TYPE_ARG4) || \
-    !defined(RECVFROM_TYPE_ARG5) || \
-    !defined(RECVFROM_TYPE_ARG6) || \
-    !defined(RECVFROM_TYPE_RETV)
-  /* */
-  Error Missing_definition_of_return_and_arguments_types_of_recvfrom
-  /* */
-#else
-#define sreadfrom(s,b,bl,f,fl) (ssize_t)recvfrom((RECVFROM_TYPE_ARG1)  (s),  \
-                                                 (RECVFROM_TYPE_ARG2 *)(b),  \
-                                                 (RECVFROM_TYPE_ARG3)  (bl), \
-                                                 (RECVFROM_TYPE_ARG4)  (0),  \
-                                                 (RECVFROM_TYPE_ARG5 *)(f),  \
-                                                 (RECVFROM_TYPE_ARG6 *)(fl))
-#endif
-#else /* HAVE_RECVFROM */
-#ifndef sreadfrom
-  /* */
-  Error Missing_definition_of_macro_sreadfrom
-  /* */
-#endif
-#endif /* HAVE_RECVFROM */
-
-
-#ifdef RECVFROM_TYPE_ARG6_IS_VOID
-#  define RECVFROM_ARG6_T int
-#else
-#  define RECVFROM_ARG6_T RECVFROM_TYPE_ARG6
-#endif
-#endif /* if 0 */
-
-
 /*
  * Function-like macro definition used to close a socket.
  */