a) refer 'perl' in their Makefile, or
b) have a directory name of p5-*, or
c) have any dependency on any p5-* package
Like last time, where this caused no complaints.
* Stop to treat NetBSD's sed as GNU sed, not full compatible.
* Then, no need to reset TOOLS_PLATFORM.gsed for NetBSD if USE_TOOLS+=gsed and
real GNU sed is required.
* In addition, convert simple USE_TOOLS+=gsed to conditionally, without NetBSD.
* convert {BUILD_,}DEPENDS+=gsed to USE_TOOLS, all tools from gsed are real gsed.
