Hi
   
I have installed pkg-config, and also I have used the command to set "export $PKG_CONFIG_LIBDIR=/usr/lib/x86_64-linux-gnu/pkgconfig",  still happens this problem.
root@gujianliang:/home/gu/bitcoin1/bitcoin# export $PKG_CONFIG_LIBDIR
bash: export: `/usr/lib/x86_64-linux-gnu/pkgconfig': not a valid identifier


And I use "git clone https://github.com/bitcoin/bitcoin.git" to download the bitcoin source code.  Do you mean the bitcoin version will impact the compiling?

thanks.

hi friends
     I have got a problem when I was doing compiling bitcoin source code, and find "configure.ac:1084: error: possibly undefined macro: PKG_CONFIG_LIBDIR", which I can not know what is the reason.
     Could anyone help me on this? I am using Ubuntu 14.04 LTS now.
     Thanks for the good guy.


root@gujianliang:/home/gu/bitcoin1/bitcoin# ./autogensh
bash: ./autogensh: No such file or directory
root@gujianliang:/home/gu/bitcoin1/bitcoin# ./autogen.sh
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
libtoolize: copying file 'build-aux/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'build-aux/m4'.
libtoolize: copying file 'build-aux/m4/libtool.m4'
libtoolize: copying file 'build-aux/m4/ltoptions.m4'
libtoolize: copying file 'build-aux/m4/ltsugar.m4'
libtoolize: copying file 'build-aux/m4/ltversion.m4'
libtoolize: copying file 'build-aux/m4/lt~obsolete.m4'
configure.ac:45: installing 'build-aux/compile'
configure.ac:28: installing 'build-aux/missing'
Makefile.am: installing 'build-aux/depcomp'
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
libtoolize: copying file 'build-aux/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'build-aux/m4'.
libtoolize: copying file 'build-aux/m4/libtool.m4'
libtoolize: copying file 'build-aux/m4/ltoptions.m4'
libtoolize: copying file 'build-aux/m4/ltsugar.m4'
libtoolize: copying file 'build-aux/m4/ltversion.m4'
libtoolize: copying file 'build-aux/m4/lt~obsolete.m4'
configure.ac:10: installing 'build-aux/compile'
configure.ac:9: installing 'build-aux/missing'
Makefile.am: installing 'build-aux/depcomp'
libtoolize: putting auxiliary files in AC_CONFIG_AUX_DIR, 'build-aux'.
libtoolize: copying file 'build-aux/ltmain.sh'
libtoolize: putting macros in AC_CONFIG_MACRO_DIRS, 'build-aux/m4'.
libtoolize: copying file 'build-aux/m4/libtool.m4'
libtoolize: copying file 'build-aux/m4/ltoptions.m4'
libtoolize: copying file 'build-aux/m4/ltsugar.m4'
libtoolize: copying file 'build-aux/m4/ltversion.m4'
libtoolize: copying file 'build-aux/m4/lt~obsolete.m4'
configure.ac:1084: error: possibly undefined macro: PKG_CONFIG_LIBDIR
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
autoreconf: /usr/local/bin/autoconf failed with exit status: 1