bsd.dep.mk: revert 1.85 (for now)

Revert my recent 1.85 revision that fixed "make tags".  It causes too
much build breakage elsewhere in the tree that needs to be resolved first.

Issues include:
- Directories using TESTS_CXX with .cpp and .cxx extension instead of the
  default .cc extension (see bsd.prog.mk). Most of these have been fixed.
- external/gpl3/gcc build of .cc files. (No idea what's wrong there).

share/mk/bsd.dep.mk

@@ -1,4 +1,4 @@
-#	$NetBSD: bsd.dep.mk,v 1.85 2020/06/21 03:39:21 lukem Exp $
+#	$NetBSD: bsd.dep.mk,v 1.86 2020/06/22 01:04:26 lukem Exp $
 
 ##### Basic targets
 realdepend:	beforedepend .depend afterdepend
@@ -94,16 +94,16 @@ _MKDEP_FILEFLAGS=
 
 ##### Clean rules
 .if defined(SRCS) && !empty(SRCS)
-CLEANDIRFILES+= .depend ${__DPSRCS.d} ${__DPSRCS.d:.d=.d.tmp} tags ${CLEANDEPEND}
+CLEANDIRFILES+= .depend ${__DPSRCS.d} ${__DPSRCS.d:.d=.d.tmp} ${.CURDIR}/tags ${CLEANDEPEND}
 .endif
 
 ##### Custom rules
-.if !commands(tags)
+.if !target(tags)
 tags: ${SRCS}
 .if defined(SRCS) && !empty(SRCS)
 	${_MKTARGET_CREATE}
-	-cd "${.CURDIR}"; ctags -f /dev/stdout ${.ALLSRC:M*.[cly]} | \
-	    ${TOOL_SED} "s;\${.CURDIR}/;;" > ${.OBJDIR}/tags
+	-cd "${.CURDIR}"; ctags -f /dev/stdout ${.ALLSRC:N*.h} | \
+	    ${TOOL_SED} "s;\${.CURDIR}/;;" > tags
 .endif
 .endif