debugging bsd.port.mk internals

There's a trick that works since we added .VARIABLES to make.

$ make verbose-show='${.VARIABLES}'

(quotes needed so make will see them but not the shell)

You generally want to sort them, and you can filter the names using the :M
construct

e.g.,

mabel$ make verbose-show='${.VARIABLES:M*LINK*}'|sort
BUILD_UNLINKED=
COMPILER_LINKS= clang /usr/bin/clang clang++ /usr/bin/clang++ cc /usr/bin/cc c++ /usr/bin/c++
LINK.F=f77 -O2
LINK.S=cc
LINK.c=cc -O2 -pipe
LINK.cc=c++ -O2 -pipe
LINK.f=f77 -O2
LINK.p=pc
LINK.r=f77 -O2
LINK.s=cc
LINKER_VERSION=lld
OCAML_NATIVE_DYNLINK_ARCHS=aarch64 amd64 i386
UNLINKED=wayland
_LINKER_FLAGS=
_PACKAGE_LINKS= amd64/ftp/arc-5.21pp0.tgz amd64/all/arc-5.21pp0.tgz