diff --git a/configure.ac b/configure.ac
index 32d0f728..e553e999 100644
--- a/configure.ac
+++ b/configure.ac
@@ -44,7 +44,7 @@ AC_PROG_MAKE_SET
 
 # Checks for header files.
 AC_HEADER_MAJOR
-AC_CHECK_HEADERS([arpa/inet.h fcntl.h langinfo.h libintl.h limits.h locale.h netinet/in.h stdint.h stdio_ext.h stdlib.h string.h sys/file.h sys/ioctl.h sys/param.h sys/time.h termios.h unistd.h utmp.h values.h wchar.h wctype.h])
+AC_CHECK_HEADERS([arpa/inet.h fcntl.h float.h langinfo.h libintl.h limits.h locale.h netinet/in.h stdint.h stdio_ext.h stdlib.h string.h sys/file.h sys/ioctl.h sys/param.h sys/time.h termios.h unistd.h utmp.h values.h wchar.h wctype.h])
 
 # Checks for typedefs, structures, and compiler characteristics.
 AC_CHECK_HEADER_STDBOOL
@@ -252,7 +252,7 @@ then
 fi
 AC_SUBST(DEJAGNU)
 
-AC_CHECK_FUNCS([__fpending alarm atexit dup2 getpagesize gettimeofday iswprint memchr memmove memset munmap nl_langinfo putenv regcomp rpmatch select setlocale strcasecmp strchr strcspn strdup strerror strncasecmp strpbrk strrchr strspn strstr strtol strtoul strtoull strverscmp uname utmpname wcwidth])
+AC_CHECK_FUNCS([__fpending alarm atexit dup2 gethostname getpagesize gettimeofday iswprint memchr memmove memset nl_langinfo putenv regcomp rpmatch select setlocale strcasecmp strchr strcspn strdup strerror strncasecmp strndup strpbrk strrchr strspn strstr strtol strtoul strtoull strverscmp utmpname wcwidth])
 
 AC_CONFIG_FILES([Makefile
                  include/Makefile