autoconf fails on OS X

[IngwiePhoenix]

First of: On MacOS, when using the homebrew package libtool, you have to use glibtoolize. After I changed that little bit in autogen.sh though, I got this:

[email protected] ~/W/G/vitamtp $ ./autogen.sh
Removing libtool cruft
Running libtoolize
glibtoolize: putting auxiliary files in '.'.
glibtoolize: copying file './ltmain.sh'
glibtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'm4'.
glibtoolize: copying file 'm4/libtool.m4'
glibtoolize: copying file 'm4/ltoptions.m4'
glibtoolize: copying file 'm4/ltsugar.m4'
glibtoolize: copying file 'm4/ltversion.m4'
glibtoolize: copying file 'm4/lt~obsolete.m4'
Removing aclocal cruft
Running aclocal -I ./m4 
configure.ac:16: warning: AC_LIB_PREPARE_PREFIX is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:16: warning: AC_LIB_RPATH is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:16: warning: AC_LIB_PREPARE_PREFIX is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:16: warning: AC_LIB_RPATH is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
Removing autoheader cruft
Running autoheader
configure.ac:16: warning: AC_LIB_PREPARE_PREFIX is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:16: warning: AC_LIB_RPATH is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
Removing automake cruft
Running automake
configure.ac:16: warning: AC_LIB_PREPARE_PREFIX is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:16: warning: AC_LIB_RPATH is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:12: installing './compile'
configure.ac:13: installing './config.guess'
configure.ac:13: installing './config.sub'
configure.ac:7: installing './install-sh'
configure.ac:7: installing './missing'
src/Makefile.am: installing './depcomp'
Removing autoconf cruft
Running autoconf
configure.ac:16: warning: AC_LIB_PREPARE_PREFIX is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure.ac:16: warning: AC_LIB_RPATH is m4_require'd but not m4_defun'd
m4/iconv.m4:18: AM_ICONV_LINKFLAGS_BODY is expanded from...
m4/iconv.m4:152: AM_ICONV_LINK is expanded from...
m4/iconv.m4:195: AM_ICONV is expanded from...
configure.ac:16: the top level
configure:12177: error: possibly undefined macro: AC_LIB_PREPARE_PREFIX
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
configure:12178: error: possibly undefined macro: AC_LIB_RPATH
configure:12183: error: possibly undefined macro: AC_LIB_LINKFLAGS_BODY
configure:12191: error: possibly undefined macro: AC_LIB_APPENDTOVAR
Finished!

Obviously, this isn't exactly "finished" since errors have been reported... How can I do away with those errors?