libxpm: enable 2nd arch, drop libXpm.la. (#691)
libxpm: enable 2nd arch, drop libXpm.la. (#691)

* Enable 2nd arch and drop documentation when building for them.
* Add devel:lib{x11,xcb,xau} to REQUIRES_devel.
* Add $secondaryArchSuffix to cmd:libtoolize in BUILD_PREREQUIRES.
* HOMEPAGE: http://xorg.freedesktop.org/ moved to https://www.x.org/.
* ARCHITECTURES: Mark as tested on x86 and x86_64.
Begasus/haikuports,moochris/haikuports,koletzky/haikuports,Begasus/haikuports,miqlas/haikuports,Begasus/haikuports,nielx/haikuports,nielx/haikuports,haikuports/haikuports,nielx/haikuports,miqlas/haikuports,haikuports/haikuports,moochris/haikuports,haikuports/haikuports,Begasus/haikuports,haikuports/haikuports,haikuports/haikuports,koletzky/haikuports,moochris/haikuports,miqlas/haikuports,koletzky/haikuports,Begasus/haikuports