diff --git a/CMakeLists.txt b/CMakeLists.txt
index 581588eb..b5c35a38 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -61,8 +61,6 @@ option(LIBXML2_WITH_ZLIB "Use libz" OFF)
 set(LIBXML2_XMLCONF_WORKING_DIR ${CMAKE_CURRENT_BINARY_DIR} CACHE PATH "Working directory for XML Conformance Test Suite")
 
 if(LIBXML2_WITH_PYTHON)
-    check_include_files(unistd.h HAVE_UNISTD_H)
-    check_symbol_exists(F_GETFL fcntl.h HAVE_F_GETFL)
     find_package(Python COMPONENTS Interpreter Development REQUIRED)
     #set(LIBXML2_PYTHON_INSTALL_DIR ${Python_SITEARCH} CACHE PATH "Python bindings install directory")
     set(LIBXML2_PYTHON_INSTALL_DIR "${CMAKE_INSTALL_PREFIX}/python"
@@ -130,11 +128,7 @@ if (NOT MSVC)
     check_include_files(dlfcn.h HAVE_DLFCN_H)
     check_library_exists(dl dlopen "" HAVE_DLOPEN)
     check_include_files(dl.h HAVE_DL_H)
-    check_include_files(fcntl.h HAVE_FCNTL_H)
-    check_function_exists(fpclass HAVE_FPCLASS)
-    check_function_exists(ftime HAVE_FTIME)
     check_function_exists(getentropy HAVE_GETENTROPY)
-    check_function_exists(gettimeofday HAVE_GETTIMEOFDAY)
     check_library_exists(history append_history "" HAVE_LIBHISTORY)
     check_library_exists(readline readline "" HAVE_LIBREADLINE)
     check_function_exists(mmap HAVE_MMAP)
@@ -143,16 +137,11 @@ if (NOT MSVC)
     check_include_files(netinet/in.h HAVE_NETINET_IN_H)
     check_include_files(poll.h HAVE_POLL_H)
     check_library_exists(dld shl_load "" HAVE_SHLLOAD)
-    check_function_exists(stat HAVE_STAT)
     check_include_files(stdint.h HAVE_STDINT_H)
     check_include_files(sys/mman.h HAVE_SYS_MMAN_H)
     check_include_files(sys/random.h HAVE_SYS_RANDOM_H)
     check_include_files(sys/select.h HAVE_SYS_SELECT_H)
     check_include_files(sys/socket.h HAVE_SYS_SOCKET_H)
-    check_include_files(sys/stat.h HAVE_SYS_STAT_H)
-    check_include_files(sys/timeb.h HAVE_SYS_TIMEB_H)
-    check_include_files(sys/time.h HAVE_SYS_TIME_H)
-    check_include_files(unistd.h HAVE_UNISTD_H)
 endif()
 
 if(LIBXML2_WITH_TLS)
diff --git a/catalog.c b/catalog.c
index 1e704647..55ea301f 100644
--- a/catalog.c
+++ b/catalog.c
@@ -19,17 +19,16 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#ifdef HAVE_SYS_STAT_H
-#include <sys/stat.h>
-#endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#elif defined (_WIN32)
-#include <io.h>
-#endif
-#ifdef HAVE_FCNTL_H
+
 #include <fcntl.h>
+#include <sys/stat.h>
+
+#ifdef _WIN32
+  #include <io.h>
+#else
+  #include <unistd.h>
 #endif
+
 #include <libxml/xmlmemory.h>
 #include <libxml/hash.h>
 #include <libxml/uri.h>
@@ -937,62 +936,33 @@ xmlParseCatalogFile(const char *filename) {
 static xmlChar *
 xmlLoadFileContent(const char *filename)
 {
-#ifdef HAVE_STAT
     int fd;
-#else
-    FILE *fd;
-#endif
     int len;
     long size;
 
-#ifdef HAVE_STAT
     struct stat info;
-#endif
     xmlChar *content;
 
     if (filename == NULL)
         return (NULL);
 
-#ifdef HAVE_STAT
     if (stat(filename, &info) < 0)
         return (NULL);
-#endif
 
-#ifdef HAVE_STAT
     fd = open(filename, O_RDONLY);
     if (fd  < 0)
-#else
-    fd = fopen(filename, "rb");
-    if (fd == NULL)
-#endif
     {
         return (NULL);
     }
-#ifdef HAVE_STAT
     size = info.st_size;
-#else
-    if (fseek(fd, 0, SEEK_END) || (size = ftell(fd)) == EOF || fseek(fd, 0, SEEK_SET)) {        /* File operations denied? ok, just close and return failure */
-        fclose(fd);
-        return (NULL);
-    }
-#endif
     content = (xmlChar*)xmlMallocAtomic(size + 10);
     if (content == NULL) {
         xmlCatalogErrMemory();
-#ifdef HAVE_STAT
 	close(fd);
-#else
-	fclose(fd);
-#endif
         return (NULL);
     }
-#ifdef HAVE_STAT
     len = read(fd, content, size);
     close(fd);
-#else
-    len = fread(content, 1, size, fd);
-    fclose(fd);
-#endif
     if (len < 0) {
         xmlFree(content);
         return (NULL);
diff --git a/config.h.cmake.in b/config.h.cmake.in
index acc838c8..f31fc3b0 100644
--- a/config.h.cmake.in
+++ b/config.h.cmake.in
@@ -16,18 +16,9 @@
 /* Define to 1 if you have the <dl.h> header file. */
 #cmakedefine HAVE_DL_H 1
 
-/* Define to 1 if you have the <fcntl.h> header file. */
-#cmakedefine HAVE_FCNTL_H 1
-
-/* Define to 1 if you have the `ftime' function. */
-#cmakedefine HAVE_FTIME 1
-
 /* Define to 1 if you have the `getentropy' function. */
 #cmakedefine HAVE_GETENTROPY 1
 
-/* Define to 1 if you have the `gettimeofday' function. */
-#cmakedefine HAVE_GETTIMEOFDAY 1
-
 /* Define if history library is there (-lhistory) */
 #cmakedefine HAVE_LIBHISTORY 1
 
@@ -60,9 +51,6 @@
 /* Have shl_load based dso */
 #cmakedefine HAVE_SHLLOAD 1
 
-/* Define to 1 if you have the `stat' function. */
-#cmakedefine HAVE_STAT 1
-
 /* Define to 1 if you have the <stdint.h> header file. */
 #cmakedefine HAVE_STDINT_H 1
 
@@ -78,18 +66,6 @@
 /* Define to 1 if you have the <sys/socket.h> header file. */
 #cmakedefine HAVE_SYS_SOCKET_H 1
 
-/* Define to 1 if you have the <sys/stat.h> header file. */
-#cmakedefine HAVE_SYS_STAT_H 1
-
-/* Define to 1 if you have the <sys/timeb.h> header file. */
-#cmakedefine HAVE_SYS_TIMEB_H 1
-
-/* Define to 1 if you have the <sys/time.h> header file. */
-#cmakedefine HAVE_SYS_TIME_H 1
-
-/* Define to 1 if you have the <unistd.h> header file. */
-#cmakedefine HAVE_UNISTD_H 1
-
 /* Define to 1 if you have the <zlib.h> header file. */
 #cmakedefine HAVE_ZLIB_H 1
 
diff --git a/configure.ac b/configure.ac
index 8a089de8..de70e705 100644
--- a/configure.ac
+++ b/configure.ac
@@ -285,16 +285,13 @@ dnl
 dnl Checks for header files.
 dnl
 AC_CHECK_HEADERS([stdint.h])
-AC_CHECK_HEADERS([fcntl.h unistd.h sys/stat.h])
-AC_CHECK_HEADERS([sys/mman.h])
-AC_CHECK_HEADERS([sys/time.h sys/timeb.h])
-AC_CHECK_HEADERS([sys/random.h])
+AC_CHECK_HEADERS([sys/mman.h sys/random.h])
 AC_CHECK_HEADERS([dl.h dlfcn.h])
 AC_CHECK_HEADERS([glob.h])
 AM_CONDITIONAL(WITH_GLOB, test "$ac_cv_header_glob_h" = "yes")
 
 dnl Checks for library functions.
-AC_CHECK_FUNCS([getentropy gettimeofday ftime stat mmap munmap])
+AC_CHECK_FUNCS([getentropy mmap munmap])
 
 AH_VERBATIM([HAVE_MUNMAP_AFTER],[/* mmap() is no good without munmap() */
 #if defined(HAVE_MMAP) && !defined(HAVE_MUNMAP)
diff --git a/dict.c b/dict.c
index 49e1c6bf..a0dc8567 100644
--- a/dict.c
+++ b/dict.c
@@ -929,9 +929,7 @@ xmlDictQLookup(xmlDictPtr dict, const xmlChar *prefix, const xmlChar *name) {
   #include <windows.h>
   #include <bcrypt.h>
 #elif defined(HAVE_GETENTROPY)
-  #ifdef HAVE_UNISTD_H
-    #include <unistd.h>
-  #endif
+  #include <unistd.h>
   #ifdef HAVE_SYS_RANDOM_H
     #include <sys/random.h>
   #endif
diff --git a/include/win32config.h b/include/win32config.h
index a25e0385..edd87633 100644
--- a/include/win32config.h
+++ b/include/win32config.h
@@ -1,10 +1,6 @@
 #ifndef __LIBXML_WIN32_CONFIG__
 #define __LIBXML_WIN32_CONFIG__
 
-#define HAVE_SYS_STAT_H
-#define HAVE_STAT
-#define HAVE_FCNTL_H
-
 #if defined(__MINGW32__) || (defined(_MSC_VER) && _MSC_VER >= 1600)
   #define HAVE_STDINT_H
 #endif
diff --git a/meson.build b/meson.build
index d638de97..3cab6916 100644
--- a/meson.build
+++ b/meson.build
@@ -234,21 +234,19 @@ config_h.set_quoted('LOCALEDIR', dir_locale)
 # header files
 xml_check_headers = [
     'stdint.h',
-    'fcntl.h',
-    'unistd.h',
-    'sys/stat.h',
     'sys/mman.h',
+    'sys/random.h',
+    'dl.h',
+    'dlfcn.h',
+    'glob.h',
+
+    # http
     'sys/socket.h',
     'netinet/in.h',
     'arpa/inet.h',
     'netdb.h',
     'sys/select.h',
     'poll.h',
-    'sys/time.h',
-    'sys/timeb.h',
-    'dl.h',
-    'dlfcn.h',
-    'glob.h',
 ]
 
 foreach header : xml_check_headers
@@ -260,9 +258,7 @@ endforeach
 # library functions
 xml_check_functions = [
     # fct             | header
-    ['gettimeofday', 'sys/time.h'],
-    ['ftime', 'sys/timeb.h'],
-    ['stat', 'sys/stat.h'],
+    ['getentropy', 'sys/random.h'],
     ['mmap', 'sys/mman.h'],
     ['munmap', 'sys/mman.h'],
 ]
diff --git a/nanohttp.c b/nanohttp.c
index 2bd3727e..21aabafc 100644
--- a/nanohttp.c
+++ b/nanohttp.c
@@ -20,11 +20,19 @@
 #include <stdlib.h>
 #include <errno.h>
 
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#elif defined (_WIN32)
+#include <fcntl.h>
+
+#ifdef _WIN32
+
 #include <io.h>
-#endif
+#include <wsockcompat.h>
+#define XML_SOCKLEN_T int
+
+#else /* _WIN32 */
+
+#include <unistd.h>
+#include <sys/time.h>
+
 #ifdef HAVE_SYS_SOCKET_H
 #include <sys/socket.h>
 #endif
@@ -40,12 +48,6 @@
   #define SUPPORT_IP6
 #endif
 #endif
-#ifdef HAVE_FCNTL_H
-#include <fcntl.h>
-#endif
-#ifdef HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
 #ifndef HAVE_POLL_H
 #ifdef HAVE_SYS_SELECT_H
 #include <sys/select.h>
@@ -53,20 +55,20 @@
 #else
 #include <poll.h>
 #endif
-#ifdef LIBXML_ZLIB_ENABLED
-#include <zlib.h>
-#endif
 
 #ifdef VMS
   #include <stropts>
   #define XML_SOCKLEN_T unsigned int
-#elif defined(_WIN32)
-  #include <wsockcompat.h>
-  #define XML_SOCKLEN_T int
 #else
   #define XML_SOCKLEN_T socklen_t
 #endif
 
+#endif /* _WIN32 */
+
+#ifdef LIBXML_ZLIB_ENABLED
+#include <zlib.h>
+#endif
+
 #include <libxml/xmlerror.h>
 #include <libxml/xmlmemory.h>
 #include <libxml/parser.h> /* for xmlStr(n)casecmp() */
diff --git a/runtest.c b/runtest.c
index cfbbd9bb..33e50434 100644
--- a/runtest.c
+++ b/runtest.c
@@ -16,15 +16,17 @@
 
 #include "libxml.h"
 #include <stdio.h>
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#elif defined (_WIN32)
-#include <io.h>
-#endif
 #include <stdlib.h>
 #include <string.h>
-#include <sys/stat.h>
+
 #include <fcntl.h>
+#include <sys/stat.h>
+
+#ifdef _WIN32
+  #include <io.h>
+#else
+  #include <unistd.h>
+#endif
 
 #include <libxml/parser.h>
 #include <libxml/parserInternals.h>
diff --git a/xmlIO.c b/xmlIO.c
index ac2cf0d2..96815cbc 100644
--- a/xmlIO.c
+++ b/xmlIO.c
@@ -13,15 +13,18 @@
 #include <stdlib.h>
 #include <errno.h>
 
-#ifdef HAVE_SYS_STAT_H
-#include <sys/stat.h>
-#endif
-#ifdef HAVE_FCNTL_H
 #include <fcntl.h>
+#include <sys/stat.h>
+
+#if defined(_WIN32)
+  #define WIN32_LEAN_AND_MEAN
+  #include <windows.h>
+  #include <io.h>
+  #include <direct.h>
+#else
+  #include <unistd.h>
 #endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#endif
+
 #ifdef LIBXML_ZLIB_ENABLED
 #include <zlib.h>
 #endif
@@ -29,13 +32,6 @@
 #include <lzma.h>
 #endif
 
-#if defined(_WIN32)
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#include <io.h>
-#include <direct.h>
-#endif
-
 #include <libxml/xmlIO.h>
 #include <libxml/xmlmemory.h>
 #include <libxml/uri.h>
@@ -363,19 +359,16 @@ xmlNormalizeWindowsPath(const xmlChar *path)
 int
 xmlCheckFilename(const char *path)
 {
-#ifdef HAVE_STAT
 #if defined(_WIN32)
     struct _stat stat_buffer;
 #else
     struct stat stat_buffer;
 #endif
     int res;
-#endif
 
     if (path == NULL)
 	return(0);
 
-#ifdef HAVE_STAT
 #if defined(_WIN32)
     {
         wchar_t *wpath;
@@ -405,7 +398,6 @@ xmlCheckFilename(const char *path)
     if (S_ISDIR(stat_buffer.st_mode))
         return 2;
 #endif
-#endif /* HAVE_STAT */
 
     return 1;
 }
diff --git a/xmllint.c b/xmllint.c
index bba83b23..65ca4236 100644
--- a/xmllint.c
+++ b/xmllint.c
@@ -17,29 +17,23 @@
 #include <errno.h>
 #include <limits.h>
 
-#ifdef HAVE_SYS_TIME_H
-#include <sys/time.h>
-#endif
-#ifdef HAVE_SYS_TIMEB_H
-#include <sys/timeb.h>
-#endif
-#ifdef HAVE_SYS_STAT_H
-#include <sys/stat.h>
-#endif
-#ifdef HAVE_FCNTL_H
 #include <fcntl.h>
+#include <sys/stat.h>
+
+#ifdef _WIN32
+  #include <io.h>
+  #include <sys/timeb.h>
+#else
+  #include <sys/time.h>
+  #include <unistd.h>
 #endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#elif defined (_WIN32)
-#include <io.h>
-#endif
+
 #ifdef HAVE_SYS_MMAN_H
-#include <sys/mman.h>
-/* seems needed for Solaris */
-#ifndef MAP_FAILED
-#define MAP_FAILED ((void *) -1)
-#endif
+  #include <sys/mman.h>
+  /* seems needed for Solaris */
+  #ifndef MAP_FAILED
+    #define MAP_FAILED ((void *) -1)
+  #endif
 #endif
 
 #include <libxml/xmlmemory.h>
diff --git a/xzlib.c b/xzlib.c
index 0d6e6384..f3b05393 100644
--- a/xzlib.c
+++ b/xzlib.c
@@ -14,17 +14,15 @@
 #include <stdlib.h>
 #include <errno.h>
 
-#ifdef HAVE_SYS_STAT_H
-#include <sys/stat.h>
-#endif
-#ifdef HAVE_FCNTL_H
 #include <fcntl.h>
+#include <sys/stat.h>
+
+#ifdef _WIN32
+  #include <io.h>
+#else
+  #include <unistd.h>
 #endif
-#ifdef HAVE_UNISTD_H
-#include <unistd.h>
-#elif defined (_WIN32)
-#include <io.h>
-#endif
+
 #ifdef LIBXML_ZLIB_ENABLED
 #include <zlib.h>
 #endif