build: assume POSIX gettimeofday() in fallback codepath, stop detecting it

The codebase no longer relies on `gettimeofday()`. It still serves as an
unconditional fallback in `ssh2_now()` on non-Windows, if no modern
alternative exists. Let us know if this causes an issue.

To simplify, make configure fast, and avoid the detection discrepancy
between autotools and cmake.

Follow-up to 0d998d16c0 #2494
Follow-up to 694d38e33e #2493
Follow-up to a43dc6d504 #2490
Follow-up to 04665fedff #2491
Follow-up to c97959e9b6 #2489
Follow-up to 9c421761bc #2341

Closes #2485

CMakeLists.txt

@@ -314,9 +314,7 @@ if(WIN32)
   if(MINGW)
     set(HAVE_UNISTD_H 1)
     set(HAVE_INTTYPES_H 1)
-    set(HAVE_GETTIMEOFDAY 1)
   elseif(MSVC)
-    set(HAVE_GETTIMEOFDAY 0)
     set(HAVE_UNISTD_H 0)
     if(MSVC_VERSION GREATER_EQUAL 1800)
       set(HAVE_INTTYPES_H 1)
@@ -347,9 +345,6 @@ if(MSVC AND ENABLE_WERROR)
   string(APPEND CMAKE_REQUIRED_FLAGS " -WX-")
 endif()
 
-if(NOT WIN32 OR MINGW)
-  check_symbol_exists("gettimeofday" "sys/time.h" HAVE_GETTIMEOFDAY)
-endif()
 if(NOT WIN32)
   check_symbol_exists("memset_s" "string.h" HAVE_MEMSET_S)
   if(NOT HAVE_MEMSET_S)

configure.ac

@@ -396,8 +396,6 @@ case $host in
     ;;
 esac
 
-AC_CHECK_FUNCS(gettimeofday)
-
 dnl Check for memset_s()
 libssh2_cv_func_memset_s="no"
 AC_MSG_CHECKING([if memset_s can be linked])

os400/libssh2_config.h

@@ -51,9 +51,6 @@
 /* use FIONBIO for non-blocking sockets */
 #undef HAVE_FIONBIO
 
-/* Define to 1 if you have the `gettimeofday' function. */
-#define HAVE_GETTIMEOFDAY 1
-
 /* Define to 1 if you have the <inttypes.h> header file. */
 #define HAVE_INTTYPES_H 1
 

src/libssh2_config_cmake.h.in

@@ -45,7 +45,6 @@
 #cmakedefine HAVE_NETINET_IN_H
 
 /* Functions */
-#cmakedefine HAVE_GETTIMEOFDAY
 #cmakedefine HAVE_MEMSET_S
 #cmakedefine HAVE_MEMSET_EXPLICIT
 

src/libssh2_setup.h

@@ -27,7 +27,6 @@
 #ifdef __MINGW32__
 #  define HAVE_UNISTD_H
 #  define HAVE_INTTYPES_H
-#  define HAVE_GETTIMEOFDAY
 #elif defined(_MSC_VER) && _MSC_VER >= 1800
 #  define HAVE_INTTYPES_H
 #endif

vms/libssh2_config.h

@@ -25,8 +25,6 @@ typedef unsigned int socklen_t; /* missing in headers on VMS */
 #define HAVE_NETINET_IN_H
 #define HAVE_ARPA_INET_H
 
-#define HAVE_GETTIMEOFDAY 1
-
 #define POSIX_C_SOURCE
 
 /* Enable the possibility of using tracing */