diff --git a/configure.ac b/configure.ac
index 34626bc..1264b17 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,6 @@ AC_INIT([libsharp], [1.0.0])
 AM_INIT_AUTOMAKE([foreign subdir-objects -Wall -Werror])
 AM_MAINTAINER_MODE([enable])
 
-AC_OPENMP
 
 dnl
 dnl Needed for linking on Windows.
@@ -26,51 +25,8 @@ dnl Enable silent build rules if this version of Automake supports them
 dnl
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
-AC_DEFUN([AX_CHECK_COMPILE_FLAG],
-[AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
-AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
-  ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
-  _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM()],
-    [AS_VAR_SET(CACHEVAR,[yes])],
-    [AS_VAR_SET(CACHEVAR,[no])])
-  _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
-AS_IF([test x"AS_VAR_GET(CACHEVAR)" = xyes],
-  [m4_default([$2], :)],
-  [m4_default([$3], :)])
-AS_VAR_POPDEF([CACHEVAR])dnl
-])dnl AX_CHECK_COMPILE_FLAGS
-
-dnl
-dnl Introduce --enable-native-optimizations command line argument to turn on
-dnl -march=native compiler flag, disabled by default.
-dnl
-AC_ARG_ENABLE(
-    [native-optimizations],
-    [AS_HELP_STRING([--enable-native-optimizations], [Enable non-portable optimizations for your own CPU by compiling with -march=native @<:@default=no@:>@])]
-)
 
 AC_PROG_CC_C99
-AS_IF(
-    [test "x$enable_native_optimizations" = "xyes"],
-    [AX_CHECK_COMPILE_FLAG([-march=native],[CC="$CC -march=native"])],
-    dnl
-    dnl FIXME: On GCC 4.4, we hit an internal compiler error unless either
-    dnl -march=native or -fno-tree-fre is specified.
-    dnl
-    [
-        AS_IF(
-            [test "x$GCC" = "xyes" -a "x`$CC -dumpversion | cut -d. -f1,2`" = "x4.4"],
-            [AX_CHECK_COMPILE_FLAG([-fno-tree-fre], [CFLAGS="$CFLAGS -fno-tree-fre"])]
-        )
-    ]
-)
-AX_CHECK_COMPILE_FLAG([-fno-math-errno],[CFLAGS="$CFLAGS -fno-math-errno"])
-AX_CHECK_COMPILE_FLAG([-fno-trapping-math],[CFLAGS="$CFLAGS -fno-trapping-math"])
-AX_CHECK_COMPILE_FLAG([-fno-rounding-math],[CFLAGS="$CFLAGS -fno-rounding-math"])
-AX_CHECK_COMPILE_FLAG([-fno-signaling-nans],[CFLAGS="$CFLAGS -fno-signaling-nans"])
-AX_CHECK_COMPILE_FLAG([-fcx-limited-range],[CFLAGS="$CFLAGS -fcx-limited-range"])
-CFLAGS="$CFLAGS $OPENMP_CFLAGS"
 
 # adding the lib to the files to link
 LIBS="-lm"