Update to 2.18.11

• No longer warn for manpages installed under share/man [1]
• Remove code to combine comments and blank lines in a section [2]
• Remove code to combine comments and blank lines [3]
• USE_PYQT sets the necessary QT USES [4]
• Only warn on lack of INSTALLS_ICONS when USES=gnome is set [5]
• Check for files that have been patched multiple times [6]

PR: 240359 [2]

		244480 [3]
		240445 [4]
		244039 [5]
		243600 [6]

Submitted by: 0mp [1] [5]

		vladimir.chukharev@gmail.com [4]
		swills [6]

Differential Revision: D23896 [1]