sh: line 1: pkg-config: command not found sh: line 1: pkg-config: command not found sh: line 1: pkg-config: command not found *** can not find package for any of (mozilla-xpcom >= 1.7, firefox-xpcom >= 1.0, mozilla-firefox-xpcom >= 1.0) *** check that one of them is properly installed and available in PKG_CONFIG_PATH at Makefile.PL line 43