duplicate .o and .a files from PKG_LIBS in g++ command

[pooryorick]

I'm using an older version of R (3.0.2), but ran into a problem where .o and .a files from the PKG_LIBS variable were showing up twice in the g++ command. The following Makevars worked better for me:

## Use the R_HOME indirection to support installations of multiple R version

UNAME := $(shell uname)

ifeq ($(UNAME), Darwin)
FRAMEWORK = -framework CoreServices
endif

OBJECTS = RcppExports.o filedatasource-unix.o filedatasource-win.o http.o httpuv.o md5.o set_invalid_parameter.o uvutil.o websockets-base.o websockets-hixie76.o websockets-hybi03.o websockets-ietf.o websockets.o ./libuv/libuv.a ./http-parser/http_parser.o ./sha1/sha1.o ./base64/base64.o 

PKG_LIBS = `$(R_HOME)/bin/Rscript -e "Rcpp:::LdFlags()"`  $(FRAMEWORK)
ifeq ($(UNAME), SunOS)
PKG_LIBS += -lkstat -lsendfile
endif
ifeq ($(UNAME), FreeBSD)
PKG_LIBS += -lkvm
endif

PKG_CPPFLAGS = -I./libuv/include -I./http-parser -I./sha1 -I./base64



.PHONY: all libuv/libuv.a http-parser/http-parser.o

all: $(SHLIB)
$(SHLIB): libuv/libuv.a http-parser/http-parser.o sha1/sha1.o base64/base64.o

libuv/libuv.a:
        $(MAKE) --directory=libuv \
                CC="$(CC)" CFLAGS="$(CFLAGS) $(CPICFLAGS)" AR="$(AR)" RANLIB="$(RANLIB)" \
    HAVE_DTRACE=0 \
                libuv.a

http-parser/http-parser.o:
        $(MAKE) --directory=http-parser \
                CC="$(CC)" CFLAGS="$(CFLAGS) $(CPICFLAGS)" AR="$(AR)" RANLIB="$(RANLIB)" \
                http_parser.o

sha1/sha1.o:
        (cd sha1 && $(CC) $(CFLAGS) $(CPICFLAGS) -c sha1.c -o sha1.o)

base64/base64.o:
        (cd base64 && $(CXX) $(ALL_CPPFLAGS) $(ALL_CXXFLAGS) -c base64.cpp -o base64.o)

[wch]

Closing because we've since revamped the Makevars file. If there's still a problem, please reopen, or file another issue.