diff --git a/aegisub/acinclude.m4 b/aegisub/acinclude.m4
index 0c746a7d5..47c43921b 100644
--- a/aegisub/acinclude.m4
+++ b/aegisub/acinclude.m4
@@ -5,5 +5,4 @@ m4_include([m4macros/ac_flag.m4])
 m4_include([m4macros/ax_pthread.m4])
 m4_include([m4macros/ax_check_gl.m4])
 m4_include([m4macros/ax_lang_compiler_ms.m4])
-m4_include([m4macros/ax_openmp.m4])
 m4_include([m4macros/check_gnu_make.m4])
diff --git a/aegisub/m4macros/ax_openmp.m4 b/aegisub/m4macros/ax_openmp.m4
deleted file mode 100644
index cd51ed6de..000000000
--- a/aegisub/m4macros/ax_openmp.m4
+++ /dev/null
@@ -1,103 +0,0 @@
-##### http://autoconf-archive.cryp.to/ax_openmp.html
-#
-# SYNOPSIS
-#
-#   AX_OPENMP([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
-#
-# DESCRIPTION
-#
-#   This macro tries to find out how to compile programs that use
-#   OpenMP a standard API and set of compiler directives for parallel
-#   programming (see http://www-unix.mcs/)
-#
-#   On success, it sets the
-#   OPENMP_CFLAGS/OPENMP_CXXFLAGS/OPENMP_F77FLAGS output variable to
-#   the flag (e.g. -omp) used both to compile *and* link OpenMP
-#   programs in the current language.
-#
-#   NOTE: You are assumed to not only compile your program with these
-#   flags, but also link it with them as well.
-#
-#   If you want to compile everything with OpenMP, you should set:
-#
-#       CFLAGS="$CFLAGS $OPENMP_CFLAGS"
-#       #OR#  CXXFLAGS="$CXXFLAGS $OPENMP_CXXFLAGS"
-#       #OR#  FFLAGS="$FFLAGS $OPENMP_FFLAGS"
-#
-#   (depending on the selected language).
-#
-#   The user can override the default choice by setting the
-#   corresponding environment variable (e.g. OPENMP_CFLAGS).
-#
-#   ACTION-IF-FOUND is a list of shell commands to run if an OpenMP
-#   flag is found, and ACTION-IF-NOT-FOUND is a list of commands to run
-#   it if it is not found. If ACTION-IF-FOUND is not specified, the
-#   default action will define HAVE_OPENMP.
-#
-# LAST MODIFICATION
-#
-#   2007-07-29
-#
-# COPYLEFT
-#
-#   Copyright (c) 2007 Steven G. Johnson <stevenj@alum.mit.edu>
-#
-#   This program is free software: you can redistribute it and/or
-#   modify it under the terms of the GNU General Public License as
-#   published by the Free Software Foundation, either version 3 of the
-#   License, or (at your option) any later version.
-#
-#   This program is distributed in the hope that it will be useful, but
-#   WITHOUT ANY WARRANTY; without even the implied warranty of
-#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-#   General Public License for more details.
-#
-#   You should have received a copy of the GNU General Public License
-#   along with this program. If not, see
-#   <http://www.gnu.org/licenses/>.
-#
-#   As a special exception, the respective Autoconf Macro's copyright
-#   owner gives unlimited permission to copy, distribute and modify the
-#   configure scripts that are the output of Autoconf when processing
-#   the Macro. You need not follow the terms of the GNU General Public
-#   License when using or distributing such scripts, even though
-#   portions of the text of the Macro appear in them. The GNU General
-#   Public License (GPL) does govern all other use of the material that
-#   constitutes the Autoconf Macro.
-#
-#   This special exception to the GPL applies to versions of the
-#   Autoconf Macro released by the Autoconf Macro Archive. When you
-#   make and distribute a modified version of the Autoconf Macro, you
-#   may extend this special exception to the GPL to apply to your
-#   modified version as well.
-
-AC_DEFUN([AX_OPENMP], [
-AC_PREREQ(2.59) dnl for _AC_LANG_PREFIX
-
-AC_CACHE_CHECK([for OpenMP flag of _AC_LANG compiler], ax_cv_[]_AC_LANG_ABBREV[]_openmp, [save[]_AC_LANG_PREFIX[]FLAGS=$[]_AC_LANG_PREFIX[]FLAGS
-ax_cv_[]_AC_LANG_ABBREV[]_openmp=unknown
-# Flags to try:  -fopenmp (gcc), -openmp (icc), -mp (SGI & PGI),
-#                -xopenmp (Sun), -omp (Tru64), -qsmp=omp (AIX), none
-ax_openmp_flags="-fopenmp -openmp -mp -xopenmp -omp -qsmp=omp none"
-if test "x$OPENMP_[]_AC_LANG_PREFIX[]FLAGS" != x; then
-  ax_openmp_flags="$OPENMP_[]_AC_LANG_PREFIX[]FLAGS $ax_openmp_flags"
-fi
-for ax_openmp_flag in $ax_openmp_flags; do
-  case $ax_openmp_flag in
-    none) []_AC_LANG_PREFIX[]FLAGS=$save[]_AC_LANG_PREFIX[] ;;
-    *) []_AC_LANG_PREFIX[]FLAGS="$save[]_AC_LANG_PREFIX[]FLAGS $ax_openmp_flag" ;;
-  esac
-  AC_TRY_LINK_FUNC(omp_set_num_threads,
-	[ax_cv_[]_AC_LANG_ABBREV[]_openmp=$ax_openmp_flag; break])
-done
-[]_AC_LANG_PREFIX[]FLAGS=$save[]_AC_LANG_PREFIX[]FLAGS
-])
-if test "x$ax_cv_[]_AC_LANG_ABBREV[]_openmp" = "xunknown"; then
-  m4_default([$2],:)
-else
-  if test "x$ax_cv_[]_AC_LANG_ABBREV[]_openmp" != "xnone"; then
-    OPENMP_[]_AC_LANG_PREFIX[]FLAGS=$ax_cv_[]_AC_LANG_ABBREV[]_openmp
-  fi
-  m4_default([$1], [AC_DEFINE(HAVE_OPENMP,1,[Define if OpenMP is enabled])])
-fi
-])dnl AX_OPENMP