customize pkg-config location

export PKG_CONFIG_PATH=/home/biglaughing/program/lib/pkgconfig

in future , no more worry about customized compile.

Reference:
http://pkg-config.freedesktop.org/wiki/

make: *** Warning: Clock skew detected. Your build may be incomplete.

while got :
make: *** Warning: Clock skew detected. Your build may be incomplete.

find . -type f | xargs touch