Merge remote-tracking branch 'dave/buildsys'

Oh god, what are we thinking thinking merging this. Hopefully this works with
only a few follow-up patches necessary.

3 files changed, 329 insertions, 250 deletions

diff --git a/m4/acinclude.m4 b/m4/acinclude.m4
new file mode 100644
index 00000000..8ea45973
--- /dev/null
+++ b/m4/acinclude.m4
@@ -0,0 +1,170 @@
+dnl acinclude.m4 - configure macros used by pacman and libalpm
+dnl Add some custom macros for pacman and libalpm
+
+dnl GCC_STACK_PROTECT_LIB
+dnl adds -lssp to LIBS if it is available
+dnl ssp is usually provided as part of libc, but was previously a separate lib
+dnl It does not hurt to add -lssp even if libc provides SSP - in that case
+dnl libssp will simply be ignored.
+AC_DEFUN([GCC_STACK_PROTECT_LIB],[
+  AC_CACHE_CHECK([whether libssp exists], ssp_cv_lib,
+    [ssp_old_libs="$LIBS"
+     LIBS="$LIBS -lssp"
+     AC_TRY_LINK(,, ssp_cv_lib=yes, ssp_cv_lib=no)
+     LIBS="$ssp_old_libs"
+    ])
+  if test $ssp_cv_lib = yes; then
+    LIBS="$LIBS -lssp"
+  fi
+])
+
+dnl GCC_STACK_PROTECT_CC
+dnl checks -fstack-protector-all with the C compiler, if it exists then updates
+dnl CFLAGS and defines ENABLE_SSP_CC
+AC_DEFUN([GCC_STACK_PROTECT_CC],[
+  AC_LANG_ASSERT(C)
+  if test "X$CC" != "X"; then
+    AC_CACHE_CHECK([whether ${CC} accepts -fstack-protector-all],
+      ssp_cv_cc,
+      [ssp_old_cflags="$CFLAGS"
+       CFLAGS="$CFLAGS -fstack-protector-all"
+       AC_TRY_COMPILE(,, ssp_cv_cc=yes, ssp_cv_cc=no)
+       CFLAGS="$ssp_old_cflags"
+      ])
+    if test $ssp_cv_cc = yes; then
+      CFLAGS="$CFLAGS -fstack-protector-all"
+      AC_DEFINE([ENABLE_SSP_CC], 1, [Define if SSP C support is enabled.])
+    fi
+  fi
+])
+
+dnl GCC_FORTIFY_SOURCE_CC
+dnl checks -D_FORTIFY_SOURCE with the C compiler, if it exists then updates
+dnl CFLAGS
+AC_DEFUN([GCC_FORTIFY_SOURCE_CC],[
+  AC_LANG_ASSERT(C)
+  if test "X$CC" != "X"; then
+    AC_MSG_CHECKING(for FORTIFY_SOURCE support)
+    AC_TRY_COMPILE([#include <features.h>], [
+      int main() {
+      #if !(__GNUC_PREREQ (4, 1) )
+      #error No FORTIFY_SOURCE support
+      #endif
+        return 0;
+      }
+    ], [
+      AC_MSG_RESULT(yes)
+      CFLAGS="$CFLAGS -D_FORTIFY_SOURCE=2"
+    ], [
+      AC_MSG_RESULT(no)
+  ])
+  fi
+])
+
+dnl GCC_VISIBILITY_CC
+dnl checks -fvisibility=internal with the C compiler, if it exists then
+dnl defines ENABLE_VISIBILITY_CC in both configure script and Makefiles
+AC_DEFUN([GCC_VISIBILITY_CC],[
+  AC_LANG_ASSERT(C)
+  if test "X$CC" != "X"; then
+    AC_CACHE_CHECK([whether ${CC} accepts -fvisibility=internal],
+      visibility_cv_cc,
+      [visibility_old_cflags="$CFLAGS"
+       CFLAGS="$CFLAGS -fvisibility=internal"
+       AC_TRY_COMPILE(,, visibility_cv_cc=yes, visibility_cv_cc=no)
+       CFLAGS="$visibility_old_cflags"
+      ])
+    if test $visibility_cv_cc = yes; then
+      AC_DEFINE([ENABLE_VISIBILITY_CC], 1, [Define if symbol visibility C support is enabled.])
+    fi
+    AM_CONDITIONAL([ENABLE_VISIBILITY_CC], test "x$visibility_cv_cc" = "xyes")
+  fi
+])
+
+dnl GCC_GNU89_INLINE_CC
+dnl checks -fgnu89-inline with the C compiler, if it exists then defines
+dnl ENABLE_GNU89_INLINE_CC in both configure script and Makefiles
+AC_DEFUN([GCC_GNU89_INLINE_CC],[
+  AC_LANG_ASSERT(C)
+  if test "X$CC" != "X"; then
+    AC_CACHE_CHECK([for -fgnu89-inline],
+    gnu89_inline_cv_cc,
+    [ gnu89_inline_old_cflags="$CFLAGS"
+      CFLAGS="$CFLAGS -fgnu89-inline"
+      AC_TRY_COMPILE(,, gnu89_inline_cv_cc=yes, gnu89_inline_cv_cc=no)
+      CFLAGS="$gnu89_inline_old_cflags"
+    ])
+    if test $gnu89_inline_cv_cc = yes; then
+      AC_DEFINE([ENABLE_GNU89_INLINE_CC], 1, [Define if gnu89 inlining semantics should be used.])
+    fi
+    AM_CONDITIONAL([ENABLE_GNU89_INLINE_CC], test "x$gnu89_inline_cv_cc" = "xyes")
+  fi
+])
+
+dnl CFLAGS_ADD(PARAMETER, VARIABLE)
+dnl Adds parameter to VARIABLE if the compiler supports it.  For example,
+dnl CFLAGS_ADD([-Wall],[WARN_FLAGS]).
+AC_DEFUN([CFLAGS_ADD],
+[AS_VAR_PUSHDEF([my_cflags], [cflags_cv_warn_$1])dnl
+AC_CACHE_CHECK([whether compiler handles $1], [my_cflags], [
+  save_CFLAGS="$CFLAGS"
+  CFLAGS="${CFLAGS} $1"
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([])],
+                    [AS_VAR_SET([my_cflags], [yes])],
+                    [AS_VAR_SET([my_cflags], [no])])
+  CFLAGS="$save_CFLAGS"
+])
+AS_VAR_PUSHDEF([new_cflags], [[$2]])dnl
+AS_VAR_IF([my_cflags], [yes], [AS_VAR_APPEND([new_cflags], [" $1"])])
+AS_VAR_POPDEF([new_cflags])dnl
+AS_VAR_POPDEF([my_cflags])dnl
+m4_ifval([$2], [AS_LITERAL_IF([$2], [AC_SUBST([$2])], [])])dnl
+])
+
+dnl Checks for getmntinfo and determines whether it uses statfs or statvfs
+AC_DEFUN([FS_STATS_TYPE],
+  [AC_CACHE_CHECK([filesystem statistics type], fs_stats_cv_type,
+    [AC_CHECK_FUNC(getmntinfo,
+      [AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[
+# include <sys/param.h>
+# include <sys/mount.h>
+#if HAVE_SYS_UCRED_H
+#include <sys/ucred.h>
+#endif
+extern int getmntinfo (struct statfs **, int);
+]],
+          [])],
+        [fs_stats_cv_type="struct statfs"],
+        [fs_stats_cv_type="struct statvfs"])],
+      [AC_CHECK_FUNC(getmntent,
+        [fs_stats_cv_type="struct statvfs"])]
+    )]
+  )
+  AC_DEFINE_UNQUOTED(FSSTATSTYPE, [$fs_stats_cv_type],
+    [Defined as the filesystem stats type ('statvfs' or 'statfs')])
+  if test $ac_cv_func_getmntinfo = yes; then
+    if test "$fs_stats_cv_type" = "struct statvfs"; then
+      AC_DEFINE([HAVE_GETMNTINFO_STATVFS], 1, [Define if getmntinfo() uses statvfs.])
+    else
+      AC_DEFINE([HAVE_GETMNTINFO_STATFS], 1, [Define if getmntinfo() uses statfs.])
+    fi
+  fi
+])
+
+dnl Checks for PATH_MAX and defines it if not present
+AC_DEFUN([PATH_MAX_DEFINED],
+  [AC_CACHE_CHECK([PATH_MAX defined], path_max_cv_defined,
+    [AC_EGREP_CPP(yes, [[
+#include <limits.h>
+#if defined(PATH_MAX)
+yes
+#endif
+]],
+      [path_max_cv_defined=yes],
+      [path_max_cv_defined=no])]
+  )
+  if test $path_max_cv_defined = no; then
+    AC_DEFINE([PATH_MAX], 4096, [Define if PATH_MAX is undefined by limits.h.])
+  fi
+])
diff --git a/m4/libcurl.m4 b/m4/libcurl.m4
deleted file mode 100644
index 01a0575c..00000000
--- a/m4/libcurl.m4
+++ /dev/null
@@ -1,250 +0,0 @@
-# LIBCURL_CHECK_CONFIG ([DEFAULT-ACTION], [MINIMUM-VERSION],
-#                       [ACTION-IF-YES], [ACTION-IF-NO])
-# ----------------------------------------------------------
-#      David Shaw <dshaw@jabberwocky.com>   May-09-2006
-#
-# Checks for libcurl.  DEFAULT-ACTION is the string yes or no to
-# specify whether to default to --with-libcurl or --without-libcurl.
-# If not supplied, DEFAULT-ACTION is yes.  MINIMUM-VERSION is the
-# minimum version of libcurl to accept.  Pass the version as a regular
-# version number like 7.10.1. If not supplied, any version is
-# accepted.  ACTION-IF-YES is a list of shell commands to run if
-# libcurl was successfully found and passed the various tests.
-# ACTION-IF-NO is a list of shell commands that are run otherwise.
-# Note that using --without-libcurl does run ACTION-IF-NO.
-#
-# This macro #defines HAVE_LIBCURL if a working libcurl setup is
-# found, and sets @LIBCURL@ and @LIBCURL_CPPFLAGS@ to the necessary
-# values.  Other useful defines are LIBCURL_FEATURE_xxx where xxx are
-# the various features supported by libcurl, and LIBCURL_PROTOCOL_yyy
-# where yyy are the various protocols supported by libcurl.  Both xxx
-# and yyy are capitalized.  See the list of AH_TEMPLATEs at the top of
-# the macro for the complete list of possible defines.  Shell
-# variables $libcurl_feature_xxx and $libcurl_protocol_yyy are also
-# defined to 'yes' for those features and protocols that were found.
-# Note that xxx and yyy keep the same capitalization as in the
-# curl-config list (e.g. it's "HTTP" and not "http").
-#
-# Users may override the detected values by doing something like:
-# LIBCURL="-lcurl" LIBCURL_CPPFLAGS="-I/usr/myinclude" ./configure
-#
-# For the sake of sanity, this macro assumes that any libcurl that is
-# found is after version 7.7.2, the first version that included the
-# curl-config script.  Note that it is very important for people
-# packaging binary versions of libcurl to include this script!
-# Without curl-config, we can only guess what protocols are available,
-# or use curl_version_info to figure it out at runtime.
-
-AC_DEFUN([LIBCURL_CHECK_CONFIG],
-[
-  AH_TEMPLATE([LIBCURL_FEATURE_SSL],[Defined if libcurl supports SSL])
-  AH_TEMPLATE([LIBCURL_FEATURE_KRB4],[Defined if libcurl supports KRB4])
-  AH_TEMPLATE([LIBCURL_FEATURE_IPV6],[Defined if libcurl supports IPv6])
-  AH_TEMPLATE([LIBCURL_FEATURE_LIBZ],[Defined if libcurl supports libz])
-  AH_TEMPLATE([LIBCURL_FEATURE_ASYNCHDNS],[Defined if libcurl supports AsynchDNS])
-  AH_TEMPLATE([LIBCURL_FEATURE_IDN],[Defined if libcurl supports IDN])
-  AH_TEMPLATE([LIBCURL_FEATURE_SSPI],[Defined if libcurl supports SSPI])
-  AH_TEMPLATE([LIBCURL_FEATURE_NTLM],[Defined if libcurl supports NTLM])
-
-  AH_TEMPLATE([LIBCURL_PROTOCOL_HTTP],[Defined if libcurl supports HTTP])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_HTTPS],[Defined if libcurl supports HTTPS])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_FTP],[Defined if libcurl supports FTP])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_FTPS],[Defined if libcurl supports FTPS])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_FILE],[Defined if libcurl supports FILE])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_TELNET],[Defined if libcurl supports TELNET])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_LDAP],[Defined if libcurl supports LDAP])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_DICT],[Defined if libcurl supports DICT])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_TFTP],[Defined if libcurl supports TFTP])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_RTSP],[Defined if libcurl supports RTSP])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_POP3],[Defined if libcurl supports POP3])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_IMAP],[Defined if libcurl supports IMAP])
-  AH_TEMPLATE([LIBCURL_PROTOCOL_SMTP],[Defined if libcurl supports SMTP])
-
-  AC_ARG_WITH(libcurl,
-     AC_HELP_STRING([--with-libcurl=PREFIX],[look for the curl library in PREFIX/lib and headers in PREFIX/include]),
-     [_libcurl_with=$withval],[_libcurl_with=ifelse([$1],,[yes],[$1])])
-
-  if test "$_libcurl_with" != "no" ; then
-
-     AC_PROG_AWK
-
-     _libcurl_version_parse="eval $AWK '{split(\$NF,A,\".\"); X=256*256*A[[1]]+256*A[[2]]+A[[3]]; print X;}'"
-
-     _libcurl_try_link=yes
-
-     if test -d "$_libcurl_with" ; then
-        LIBCURL_CPPFLAGS="-I$withval/include"
-        _libcurl_ldflags="-L$withval/lib"
-        AC_PATH_PROG([_libcurl_config],[curl-config],[],
-                     ["$withval/bin"])
-     else
-        AC_PATH_PROG([_libcurl_config],[curl-config],[],[$PATH])
-     fi
-
-     if test x$_libcurl_config != "x" ; then
-        AC_CACHE_CHECK([for the version of libcurl],
-           [libcurl_cv_lib_curl_version],
-           [libcurl_cv_lib_curl_version=`$_libcurl_config --version | $AWK '{print $[]2}'`])
-
-        _libcurl_version=`echo $libcurl_cv_lib_curl_version | $_libcurl_version_parse`
-        _libcurl_wanted=`echo ifelse([$2],,[0],[$2]) | $_libcurl_version_parse`
-
-        if test $_libcurl_wanted -gt 0 ; then
-           AC_CACHE_CHECK([for libcurl >= version $2],
-              [libcurl_cv_lib_version_ok],
-              [
-              if test $_libcurl_version -ge $_libcurl_wanted ; then
-                 libcurl_cv_lib_version_ok=yes
-              else
-                 libcurl_cv_lib_version_ok=no
-              fi
-              ])
-        fi
-
-        if test $_libcurl_wanted -eq 0 || test x$libcurl_cv_lib_version_ok = xyes ; then
-           if test x"$LIBCURL_CPPFLAGS" = "x" ; then
-              LIBCURL_CPPFLAGS=`$_libcurl_config --cflags`
-           fi
-           if test x"$LIBCURL" = "x" ; then
-              LIBCURL=`$_libcurl_config --libs`
-
-              # This is so silly, but Apple actually has a bug in their
-              # curl-config script.  Fixed in Tiger, but there are still
-              # lots of Panther installs around.
-              case "${host}" in
-                 powerpc-apple-darwin7*)
-                    LIBCURL=`echo $LIBCURL | sed -e 's|-arch i386||g'`
-                 ;;
-              esac
-           fi
-
-           # All curl-config scripts support --feature
-           _libcurl_features=`$_libcurl_config --feature`
-
-           # Is it modern enough to have --protocols? (7.12.4)
-           if test $_libcurl_version -ge 461828 ; then
-              _libcurl_protocols=`$_libcurl_config --protocols`
-           fi
-        else
-           _libcurl_try_link=no
-        fi
-
-        unset _libcurl_wanted
-     fi
-
-     if test $_libcurl_try_link = yes ; then
-
-        # we didn't find curl-config, so let's see if the user-supplied
-        # link line (or failing that, "-lcurl") is enough.
-        LIBCURL=${LIBCURL-"$_libcurl_ldflags -lcurl"}
-
-        AC_CACHE_CHECK([whether libcurl is usable],
-           [libcurl_cv_lib_curl_usable],
-           [
-           _libcurl_save_cppflags=$CPPFLAGS
-           CPPFLAGS="$LIBCURL_CPPFLAGS $CPPFLAGS"
-           _libcurl_save_libs=$LIBS
-           LIBS="$LIBCURL $LIBS"
-
-           AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <curl/curl.h>],[
-/* Try and use a few common options to force a failure if we are
-   missing symbols or can't link. */
-int x;
-curl_easy_setopt(NULL,CURLOPT_URL,NULL);
-x=CURL_ERROR_SIZE;
-x=CURLOPT_WRITEFUNCTION;
-x=CURLOPT_FILE;
-x=CURLOPT_ERRORBUFFER;
-x=CURLOPT_STDERR;
-x=CURLOPT_VERBOSE;
-])],libcurl_cv_lib_curl_usable=yes,libcurl_cv_lib_curl_usable=no)
-
-           CPPFLAGS=$_libcurl_save_cppflags
-           LIBS=$_libcurl_save_libs
-           unset _libcurl_save_cppflags
-           unset _libcurl_save_libs
-           ])
-
-        if test $libcurl_cv_lib_curl_usable = yes ; then
-
-           # Does curl_free() exist in this version of libcurl?
-           # If not, fake it with free()
-
-           _libcurl_save_cppflags=$CPPFLAGS
-           CPPFLAGS="$CPPFLAGS $LIBCURL_CPPFLAGS"
-           _libcurl_save_libs=$LIBS
-           LIBS="$LIBS $LIBCURL"
-
-           AC_CHECK_FUNC(curl_free,,
-              AC_DEFINE(curl_free,free,
-                [Define curl_free() as free() if our version of curl lacks curl_free.]))
-
-           CPPFLAGS=$_libcurl_save_cppflags
-           LIBS=$_libcurl_save_libs
-           unset _libcurl_save_cppflags
-           unset _libcurl_save_libs
-
-           AC_DEFINE(HAVE_LIBCURL,1,
-             [Define to 1 if you have a functional curl library.])
-           AC_SUBST(LIBCURL_CPPFLAGS)
-           AC_SUBST(LIBCURL)
-
-           for _libcurl_feature in $_libcurl_features ; do
-              AC_DEFINE_UNQUOTED(AS_TR_CPP(libcurl_feature_$_libcurl_feature),[1])
-              eval AS_TR_SH(libcurl_feature_$_libcurl_feature)=yes
-           done
-
-           if test "x$_libcurl_protocols" = "x" ; then
-
-              # We don't have --protocols, so just assume that all
-              # protocols are available
-              _libcurl_protocols="HTTP FTP FILE TELNET LDAP DICT TFTP"
-
-              if test x$libcurl_feature_SSL = xyes ; then
-                 _libcurl_protocols="$_libcurl_protocols HTTPS"
-
-                 # FTPS wasn't standards-compliant until version
-                 # 7.11.0 (0x070b00 == 461568)
-                 if test $_libcurl_version -ge 461568; then
-                    _libcurl_protocols="$_libcurl_protocols FTPS"
-                 fi
-              fi
-
-              # RTSP, IMAP, POP3 and SMTP were added in
-              # 7.20.0 (0x071400 == 463872)
-              if test $_libcurl_version -ge 463872; then
-                 _libcurl_protocols="$_libcurl_protocols RTSP IMAP POP3 SMTP"
-              fi
-           fi
-
-           for _libcurl_protocol in $_libcurl_protocols ; do
-              AC_DEFINE_UNQUOTED(AS_TR_CPP(libcurl_protocol_$_libcurl_protocol),[1])
-              eval AS_TR_SH(libcurl_protocol_$_libcurl_protocol)=yes
-           done
-        else
-           unset LIBCURL
-           unset LIBCURL_CPPFLAGS
-        fi
-     fi
-
-     unset _libcurl_try_link
-     unset _libcurl_version_parse
-     unset _libcurl_config
-     unset _libcurl_feature
-     unset _libcurl_features
-     unset _libcurl_protocol
-     unset _libcurl_protocols
-     unset _libcurl_version
-     unset _libcurl_ldflags
-  fi
-
-  if test x$_libcurl_with = xno || test x$libcurl_cv_lib_curl_usable != xyes ; then
-     # This is the IF-NO path
-     ifelse([$4],,:,[$4])
-  else
-     # This is the IF-YES path
-     ifelse([$3],,:,[$3])
-  fi
-
-  unset _libcurl_with
-])dnl
diff --git a/m4/pkg.m4 b/m4/pkg.m4
new file mode 100644
index 00000000..5152a4b1
--- /dev/null
+++ b/m4/pkg.m4
@@ -0,0 +1,159 @@
+# pkg.m4 - Macros to locate and utilise pkg-config.            -*- Autoconf -*-
+# serial 1 (pkg-config-0.24)
+#
+# Copyright © 2004 Scott James Remnant <scott@netsplit.com>.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+#
+# As a special exception to the GNU General Public License, if you
+# distribute this file as part of a program that contains a
+# configuration script generated by Autoconf, you may include it under
+# the same distribution terms that you use for the rest of that program.
+
+# PKG_PROG_PKG_CONFIG([MIN-VERSION])
+# ----------------------------------
+AC_DEFUN([PKG_PROG_PKG_CONFIG],
+[m4_pattern_forbid([^_?PKG_[A-Z_]+$])
+m4_pattern_allow([^PKG_CONFIG(_(PATH|LIBDIR|SYSROOT_DIR|ALLOW_SYSTEM_(CFLAGS|LIBS)))?$])
+m4_pattern_allow([^PKG_CONFIG_(DISABLE_UNINSTALLED|TOP_BUILD_DIR|DEBUG_SPEW)$])
+AC_ARG_VAR([PKG_CONFIG], [path to pkg-config utility])
+AC_ARG_VAR([PKG_CONFIG_PATH], [directories to add to pkg-config's search path])
+AC_ARG_VAR([PKG_CONFIG_LIBDIR], [path overriding pkg-config's built-in search path])
+
+if test "x$ac_cv_env_PKG_CONFIG_set" != "xset"; then
+	AC_PATH_TOOL([PKG_CONFIG], [pkg-config])
+fi
+if test -n "$PKG_CONFIG"; then
+	_pkg_min_version=m4_default([$1], [0.9.0])
+	AC_MSG_CHECKING([pkg-config is at least version $_pkg_min_version])
+	if $PKG_CONFIG --atleast-pkgconfig-version $_pkg_min_version; then
+		AC_MSG_RESULT([yes])
+	else
+		AC_MSG_RESULT([no])
+		PKG_CONFIG=""
+	fi
+fi[]dnl
+])# PKG_PROG_PKG_CONFIG
+
+# PKG_CHECK_EXISTS(MODULES, [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
+#
+# Check to see whether a particular set of modules exists.  Similar
+# to PKG_CHECK_MODULES(), but does not set variables or print errors.
+#
+# Please remember that m4 expands AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+# only at the first occurence in configure.ac, so if the first place
+# it's called might be skipped (such as if it is within an "if", you
+# have to call PKG_CHECK_EXISTS manually
+# --------------------------------------------------------------
+AC_DEFUN([PKG_CHECK_EXISTS],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+if test -n "$PKG_CONFIG" && \
+    AC_RUN_LOG([$PKG_CONFIG --exists --print-errors "$1"]); then
+  m4_default([$2], [:])
+m4_ifvaln([$3], [else
+  $3])dnl
+fi])
+
+# _PKG_CONFIG([VARIABLE], [COMMAND], [MODULES])
+# ---------------------------------------------
+m4_define([_PKG_CONFIG],
+[if test -n "$$1"; then
+    pkg_cv_[]$1="$$1"
+ elif test -n "$PKG_CONFIG"; then
+    PKG_CHECK_EXISTS([$3],
+                     [pkg_cv_[]$1=`$PKG_CONFIG --[]$2 "$3" 2>/dev/null`
+		      test "x$?" != "x0" && pkg_failed=yes ],
+		     [pkg_failed=yes])
+ else
+    pkg_failed=untried
+fi[]dnl
+])# _PKG_CONFIG
+
+# _PKG_SHORT_ERRORS_SUPPORTED
+# -----------------------------
+AC_DEFUN([_PKG_SHORT_ERRORS_SUPPORTED],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])
+if $PKG_CONFIG --atleast-pkgconfig-version 0.20; then
+        _pkg_short_errors_supported=yes
+else
+        _pkg_short_errors_supported=no
+fi[]dnl
+])# _PKG_SHORT_ERRORS_SUPPORTED
+
+
+# PKG_CHECK_MODULES(VARIABLE-PREFIX, MODULES, [ACTION-IF-FOUND],
+# [ACTION-IF-NOT-FOUND])
+#
+#
+# Note that if there is a possibility the first call to
+# PKG_CHECK_MODULES might not happen, you should be sure to include an
+# explicit call to PKG_PROG_PKG_CONFIG in your configure.ac
+#
+#
+# --------------------------------------------------------------
+AC_DEFUN([PKG_CHECK_MODULES],
+[AC_REQUIRE([PKG_PROG_PKG_CONFIG])dnl
+AC_ARG_VAR([$1][_CFLAGS], [C compiler flags for $1, overriding pkg-config])dnl
+AC_ARG_VAR([$1][_LIBS], [linker flags for $1, overriding pkg-config])dnl
+
+pkg_failed=no
+AC_MSG_CHECKING([for $1])
+
+_PKG_CONFIG([$1][_CFLAGS], [cflags], [$2])
+_PKG_CONFIG([$1][_LIBS], [libs], [$2])
+
+m4_define([_PKG_TEXT], [Alternatively, you may set the environment variables $1[]_CFLAGS
+and $1[]_LIBS to avoid the need to call pkg-config.
+See the pkg-config man page for more details.])
+
+if test $pkg_failed = yes; then
+	AC_MSG_RESULT([no])
+	_PKG_SHORT_ERRORS_SUPPORTED
+	if test $_pkg_short_errors_supported = yes; then
+		$1[]_PKG_ERRORS=`$PKG_CONFIG --short-errors --print-errors --cflags --libs "$2" 2>&1`
+	else
+		$1[]_PKG_ERRORS=`$PKG_CONFIG --print-errors --cflags --libs "$2" 2>&1`
+	fi
+	# Put the nasty error message in config.log where it belongs
+	echo "$$1[]_PKG_ERRORS" >&AS_MESSAGE_LOG_FD
+
+	m4_default([$4], [AC_MSG_ERROR(
+[Package requirements ($2) were not met:
+
+$$1_PKG_ERRORS
+
+Consider adjusting the PKG_CONFIG_PATH environment variable if you
+installed software in a non-standard prefix.
+
+_PKG_TEXT])[]dnl
+	])
+elif test $pkg_failed = untried; then
+	AC_MSG_RESULT([no])
+	m4_default([$4], [AC_MSG_FAILURE(
+[The pkg-config script could not be found or is too old.  Make sure it
+is in your PATH or set the PKG_CONFIG environment variable to the full
+path to pkg-config.
+
+_PKG_TEXT
+
+To get pkg-config, see <http://pkg-config.freedesktop.org/>.])[]dnl
+])
+else
+	$1[]_CFLAGS=$pkg_cv_[]$1[]_CFLAGS
+	$1[]_LIBS=$pkg_cv_[]$1[]_LIBS
+	AC_MSG_RESULT([yes])
+	$3
+fi[]dnl
+])# PKG_CHECK_MODULES