Add ELF Tool Chain's c++filt to the build

Differential Revision:	https://reviews.freebsd.org/D2408
Reviewed by:	brooks, imp
Sponsored by:	The FreeBSD Foundation

gnu/usr.bin/cc/Makefile

@@ -12,7 +12,10 @@ SUBDIR+= cpp
 .endif
 
 .if ${MK_CXX} != "no"
-SUBDIR+= cc1plus c++ c++filt
+SUBDIR+= cc1plus c++
+.if ${MK_ELFTOOLCHAIN_TOOLS} == "no"
+SUBDIR+= c++filt
+.endif
 .endif
 
 .if ${MK_GCOV} != "no"

tools/build/mk/OptionalObsoleteFiles.inc

@@ -1004,7 +1004,9 @@ OLD_DIRS+=usr/include/fs/cuse
 .if ${MK_CXX} == no
 OLD_FILES+=usr/bin/CC
 OLD_FILES+=usr/bin/c++
+.if ${MK_ELFTOOLCHAIN_TOOLS} == no
 OLD_FILES+=usr/bin/c++filt
+.endif
 OLD_FILES+=usr/bin/g++
 OLD_FILES+=usr/libexec/cc1plus
 .if ${MK_GCC} == no

usr.bin/Makefile

@@ -36,6 +36,7 @@ SUBDIR=	${_addr2line} \
 	csplit \
 	ctlstat \
 	cut \
+	${_cxxfilt} \
 	demandoc \
 	dirname \
 	dpv \
@@ -237,6 +238,7 @@ SUBDIR+=	ee
 
 .if ${MK_ELFTOOLCHAIN_TOOLS} != "no"
 _addr2line=	addr2line
+_cxxfilt=	cxxfilt
 _elfcopy=	elfcopy
 _nm=		nm
 _readelf=	readelf