Previous versions
$ echo "==$(pkg-config --cflags-only-I openssl)=="
== ==
New version
$ echo "==$(pkg-config --cflags-only-I openssl)=="
====
This space to empty string output can breaks some poorly written
autoconf script.
Remi.
P.S.1: I hope it could helps some packager...
avoid losing too much time on this...
P.S.2: example of broken script
http://git.php.net/?p=php-src.git;a=commitdiff;h=640e72ce91d8e591b92cd93c...