• Belatedly update GNU grep to version 3.3
• Allow to build against GNU sigsegv (LIBSIGSEGV_DESC was shamelessly stolen from `devel/m4') but retain existing OPTIONS_DEFAULT for now
• Do not pass preprocessor and linker flags directly, USES+=pkgconfig
• PCRE_CONFIGURE_OFF is not needed when PCRE_CONFIGURE_ENABLE is used
• Convert to option helper target (post-patch-NLS-off)

Approved by: maintainer (johans: numerous timeouts on GNU tools)