Airprob compiling error

[Marten Christophe]

Hello All,

while I'm configuring airprobe/gsm-receiver i'm getting error, plz help me
=====
checking for libosmocore >= 0.1.13... Requested 'libosmocore >=
0.1.13' but version of Osmocom Core Library is UNKNOWN  <<<<<<

=====
configure: error: Library requirements (libosmocore >= 0.1.13) not
met; consider adjusting the PKG_CONFIG_PATH environment variable if
your libraries are in a nonstandard prefix so pkg-config can find
them.   <<<<<<<<
=========
plz help me to tell how i can set PKG_CONFIG_PATH  for libosmocore

Kind Regards,