pkg/53607: wm/evilwm: default configuration obliterated

[izaac%setec.org@localhost]

>Number:         53607
>Category:       pkg
>Synopsis:       use of OPT_CPPFLAGS overwrites CPPFLAGS in shipped Makefile
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Sep 14 17:25:00 +0000 2018
>Originator:     Izaac
>Release:        
>Organization:
>Environment:
>Description:
        - use of MAKE_FLAGS to set OPT_CPPFLAGS blows away the default
          configuration in the third-party makefile which is constructed by += itself
        - the result is that every actual feature of the window manager is disabled
>How-To-Repeat:
	( cd /usr/pkgsrc/wm/evilwm && bmake install )
	- use wm and discover that virtual desktops are gone
	- use wm and discover solid drags really drag
	- etc.
>Fix:
	Three options:
	1. revert to version 1.34 and recognize that -D_XOPEN_SOURCE wasn't really a thing
        2. expand MAKE_FLAGS to include the other OPT_CPPFLAGS defaults, i.e.
		-DINFOBANNER -DRANDR -DSHAPE -DSOLIDDRAG -DSTDIO -DVWM and add OPT_LDLIBS flags
		-lXrandr -lXext alike
        3. options.mk-ify the ten features and set appropriate defaults

        Any which way, an audit of jperkin's work is clearly necessary because
	things touched by him have a tendency to turn to shit.