kernel: 3.18-rc4 -> 3.18-rc5
nginxUnstable: disable the broken syslog patch
pidgin-with-plugins: fix plugin directories (close #5009)
pidgin: enableParallelBuilding
emacs24Macport: emacs-24.4-mac-5.0 -> emacs-24.4-mac-5.1
db-*: only use the osx.patch for db5 where it applies

This unbreaks builds of all other versions (4.* and 6.*).