Build and install collect2. This is needed for some C++ programs.

gnu/usr.bin/cc/Makefile

@@ -11,6 +11,9 @@ SUBDIR+= cpp
 
 .if !defined(NO_CXX)
 SUBDIR+= cc1plus c++ c++filt doc
+.if !defined(NO_COLLECT2)
+SUBDIR+= collect2
+.endif
 .endif
 
 .if !defined(NO_OBJC)

gnu/usr.bin/cc/collect2/Makefile

@@ -4,4 +4,27 @@
 
 .PATH: ${GCCDIR}
 
+PROG=	collect2
+SRCS=	collect2.c cplus-dem.c tlink.c underscore.c
+BINDIR=	/usr/libexec
+NOMAN=
+NOSHARED?=yes
+
+DPADD+=	${LIBCC_INT}
+LDADD+=	${LIBCC_INT}
+
+CLEANFILES= tmp-dum.c tmp-dum.s underscore.c
+underscore.c: Makefile
+	echo "int xxy_us_dummy;" >tmp-dum.c
+	${CC} -S tmp-dum.c
+	echo '/*WARNING: This file is automatically generated!*/' >underscore.c
+	if grep _xxy_us_dummy tmp-dum.s > /dev/null ; then \
+	  echo "int prepends_underscore = 1;" >>underscore.c; \
+	else \
+	  echo "int prepends_underscore = 0;" >>underscore.c; \
+	fi
+	# wrong to do this here, but easiest way out to duplicate gcc.c.
+	echo "char *xstrerror(int e) { return strerror(e); }" >>underscore.c
+	rm -f tmp-dum.c tmp-dum.s
+
 .include <bsd.prog.mk>