diff --git a/config.h.cmake b/config.h.cmake
index 293ae803d..f4e3a1472 100644
--- a/config.h.cmake
+++ b/config.h.cmake
@@ -1,27 +1,9 @@
-#cmakedefine HAVE_ARPA_INET_H
 #cmakedefine HAVE_LIBINTL_H
-#cmakedefine HAVE_LIMITS_H
-#cmakedefine HAVE_LOCALE_H
-#cmakedefine HAVE_NETDB_H
-#cmakedefine HAVE_NETINET_IN_H
-#cmakedefine HAVE_STDLIB_H
-#cmakedefine HAVE_STRING_H
-#cmakedefine HAVE_SYS_SOCKET_H
-#cmakedefine HAVE_SYS_TIME_H
-#cmakedefine HAVE_SYS_TYPES_H
-#cmakedefine HAVE_UNISTD_H
-#cmakedefine HAVE_PWD_H
-#cmakedefine HAVE_ERRNO_H
-#cmakedefine HAVE_REGEX_H
-#cmakedefine HAVE_WCHAR_H
-#cmakedefine HAVE_SYS_FILE_H
 #cmakedefine HAVE_SYS_RESOURCE_H
 #cmakedefine HAVE_FLOCK
 #cmakedefine HAVE_LANGINFO_CODESET
-#cmakedefine HAVE_STRNDUP
 #cmakedefine HAVE_BACKTRACE
 #cmakedefine ICONV_2ARG_IS_CONST 1
-#cmakedefine HAVE_TCL_CREATE_NS
 #cmakedefine HAVE_MALLINFO
 #cmakedefine HAVE_EAT_NEWLINE_GLITCH
 #define PACKAGE_VERSION "@VERSION@"
diff --git a/configure.in b/configure.in
index 1c4755e84..75e7082a3 100644
--- a/configure.in
+++ b/configure.in
@@ -68,7 +68,7 @@ AC_CHECK_LIB(ncursesw, initscr, LIBNCURSESW_FOUND=1, LIBNCURSESW_FOUND=0)
 
 # Checks for header files
 AC_HEADER_STDC
-AC_CHECK_HEADERS([arpa/inet.h libintl.h limits.h locale.h netdb.h netinet/in.h stdlib.h string.h sys/socket.h sys/time.h sys/types.h unistd.h pwd.h errno.h regex.h wchar.h sys/file.h sys/resource.h])
+AC_CHECK_HEADERS([libintl.h sys/resource.h])
 
 # Checks for typedefs, structures, and compiler characteristics
 AC_HEADER_TIME
@@ -91,7 +91,7 @@ AC_MSG_RESULT($ac_cv_type_socklen_t)
 # Checks for library functions.
 AC_FUNC_SELECT_ARGTYPES
 AC_TYPE_SIGNAL
-AC_CHECK_FUNCS([gethostbyname gethostname getsockname gettimeofday inet_ntoa memset mkdir select setlocale socket strcasecmp strchr strdup strndup strncasecmp strpbrk strrchr strstr regexec mallinfo])
+AC_CHECK_FUNCS([mallinfo])
 
 # Variables in config.h
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 6296b8a05..acb734144 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -34,46 +34,11 @@ INCLUDE(CheckIncludeFiles)
 INCLUDE(CheckFunctionExists)
 INCLUDE(CheckSymbolExists)
 
-CHECK_INCLUDE_FILES("arpa/inet.h" HAVE_ARPA_INET_H)
-CHECK_INCLUDE_FILES("limits.h" HAVE_LIMITS_H)
-CHECK_INCLUDE_FILES("locale.h" HAVE_LOCALE_H)
-CHECK_INCLUDE_FILES("netdb.h" HAVE_NETDB_H)
-CHECK_INCLUDE_FILES("netinet/in.h" HAVE_NETINET_IN_H)
-CHECK_INCLUDE_FILES("stdlib.h" HAVE_STDLIB_H)
-CHECK_INCLUDE_FILES("string.h" HAVE_STRING_H)
-CHECK_INCLUDE_FILES("sys/socket.h" HAVE_SYS_SOCKET_H)
-CHECK_INCLUDE_FILES("sys/time.h" HAVE_SYS_TIME_H)
-CHECK_INCLUDE_FILES("sys/types.h" HAVE_SYS_TYPES_H)
-CHECK_INCLUDE_FILES("unistd.h" HAVE_UNISTD_H)
-CHECK_INCLUDE_FILES("pwd.h" HAVE_PWD_H)
-CHECK_INCLUDE_FILES("errno.h" HAVE_ERRNO_H)
-CHECK_INCLUDE_FILES("wchar.h" HAVE_WCHAR_H)
 CHECK_INCLUDE_FILES("langinfo.h" HAVE_LANGINFO_CODESET)
 CHECK_INCLUDE_FILES("sys/resource.h" HAVE_SYS_RESOURCE_H)
 
-CHECK_FUNCTION_EXISTS(gethostbyname HAVE_GETHOSTBYNAME)
-CHECK_FUNCTION_EXISTS(gethostname HAVE_GETHOSTNAME)
-CHECK_FUNCTION_EXISTS(getsockname HAVE_GETSOCKNAME)
-CHECK_FUNCTION_EXISTS(gettimeofday HAVE_GETTIMEOFDAY)
-CHECK_FUNCTION_EXISTS(inet_ntoa HAVE_INET_NTOA)
-CHECK_FUNCTION_EXISTS(memset HAVE_MEMSET)
-CHECK_FUNCTION_EXISTS(mkdir HAVE_MKDIR)
-CHECK_FUNCTION_EXISTS(select HAVE_SELECT)
-CHECK_FUNCTION_EXISTS(setlocale HAVE_SETLOCALE)
-CHECK_FUNCTION_EXISTS(socket HAVE_SOCKET)
-CHECK_FUNCTION_EXISTS(strcasecmp HAVE_STRCASECMP)
-CHECK_FUNCTION_EXISTS(strchr HAVE_STRCHR)
-CHECK_FUNCTION_EXISTS(strdup HAVE_STRDUP)
-CHECK_FUNCTION_EXISTS(strndup HAVE_STRNDUP)
-CHECK_FUNCTION_EXISTS(strncasecmp HAVE_STRNCASECMP)
-CHECK_FUNCTION_EXISTS(strpbrk HAVE_STRPBRK)
-CHECK_FUNCTION_EXISTS(strrchr HAVE_STRRCHR)
-CHECK_FUNCTION_EXISTS(strstr HAVE_STRSTR)
 CHECK_FUNCTION_EXISTS(mallinfo HAVE_MALLINFO)
 
-CHECK_INCLUDE_FILES("regex.h" HAVE_REGEX_H)
-CHECK_FUNCTION_EXISTS(regexec HAVE_REGEXEC)
-
 CHECK_SYMBOL_EXISTS("eat_newline_glitch" "term.h" HAVE_EAT_NEWLINE_GLITCH)
 
 # weechat_gui_common MUST be the first lib in the list
diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index e4e42b99c..9122f4234 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -47,7 +47,6 @@ wee-version.c wee-version.h)
 
 # Check for flock support
 INCLUDE(CheckSymbolExists)
-CHECK_INCLUDE_FILES("sys/file.h" HAVE_SYS_FILE_H)
 CHECK_SYMBOL_EXISTS(flock "sys/file.h" HAVE_FLOCK)
 
 IF(${CMAKE_SYSTEM_NAME} STREQUAL "FreeBSD")