Replaced PKG_CHECK_MODULES with AC_CHECKs in libprocess configure.ac.
Replaced PKG_CHECK_MODULES with AC_CHECKs in libprocess configure.ac.

Review: https://reviews.apache.org/r/25031

verizonlabs/mesos,asamerh4/mesos,dforsyth/mesos,chhsia0/mesos,andschwa/mesos,chhsia0/mesos,andschwa/mesos,reneploetz/mesos,craimbert/mesos,abudnik/mesos,kaysoky/mesos,verizonlabs/mesos,chhsia0/mesos,Aman-Jain-14/customizedMesos,chhsia0/mesos,chhsia0/mesos,dforsyth/mesos,chhsia0/mesos,gsantovena/mesos,Aman-Jain-14/customizedMesos,gsantovena/mesos,kaysoky/mesos,asamerh4/mesos,verizonlabs/mesos,neilconway/mesos,yuquanshan/customizedMesos,dforsyth/mesos,kaysoky/mesos,verizonlabs/mesos,zmalik/mesos,jpeach/mesos,asamerh4/mesos,gsantovena/mesos,Gilbert88/mesos,reneploetz/mesos,reneploetz/mesos,chhsia0/mesos,kaysoky/mesos,abudnik/mesos,kaysoky/mesos,dforsyth/mesos,yuquanshan/customizedMesos,reneploetz/mesos,reneploetz/mesos,andschwa/mesos,abudnik/mesos,dforsyth/mesos,neilconway/mesos,jpeach/mesos,asamerh4/mesos,zmalik/mesos,Aman-Jain-14/customizedMesos,jpeach/mesos,Gilbert88/mesos,Aman-Jain-14/customizedMesos,abudnik/mesos,craimbert/mesos,verizonlabs/mesos,Aman-Jain-14/customizedMesos,yuquanshan/customizedMesos,andschwa/mesos,zmalik/mesos,jpeach/mesos,verizonlabs/mesos,Aman-Jain-14/customizedMesos,zmalik/mesos,yuquanshan/customizedMesos,kaysoky/mesos,craimbert/mesos,neilconway/mesos,Gilbert88/mesos,neilconway/mesos,zmalik/mesos,gsantovena/mesos,andschwa/mesos,verizonlabs/mesos,craimbert/mesos,dforsyth/mesos,reneploetz/mesos,gsantovena/mesos,yuquanshan/customizedMesos,andschwa/mesos,yuquanshan/customizedMesos,asamerh4/mesos,craimbert/mesos,neilconway/mesos,Gilbert88/mesos,gsantovena/mesos,craimbert/mesos,Aman-Jain-14/customizedMesos,Gilbert88/mesos,Gilbert88/mesos,asamerh4/mesos,craimbert/mesos,abudnik/mesos,asamerh4/mesos,jpeach/mesos,gsantovena/mesos,yuquanshan/customizedMesos,andschwa/mesos,neilconway/mesos,reneploetz/mesos,zmalik/mesos,Gilbert88/mesos,zmalik/mesos,kaysoky/mesos,neilconway/mesos,abudnik/mesos,jpeach/mesos,dforsyth/mesos,abudnik/mesos,jpeach/mesos