Make ar invocation more portable

armar doesn't understand the syntax without dash. OTOH, the syntax with dash
is the only one specified by POSIX, and it's accepted by GNU ar, BSD ar (as
bundled with OS X) and armar, so it looks like the most portable syntax.

fixes #386

ChangeLog

@@ -5,7 +5,8 @@ mbed TLS ChangeLog (Sorted per branch, date)
 Bugfix
    * Fix bug in mbedtls_mpi_add_mpi() that caused wrong results when the three
      arguments where the same (in-place doubling). Found and fixed by Janos
-     Follath.
+     Follath. #309
+   * Fix issue in Makefile that prevented building using armar. #386
 
 = mbed TLS 1.3.16 released 2016-01-05
 

library/Makefile

@@ -93,9 +93,9 @@ endif
 
 libmbedtls.a: $(OBJS)
 	echo "  AR    $@"
-	$(AR) rc $@ $(OBJS)
+	$(AR) -rc $@ $(OBJS)
 	echo "  RL    $@"
-	$(AR) s $@
+	$(AR) -s $@
 
 libpolarssl.$(DLEXT): libmbedtls.$(DLEXT)
 	echo "  LN    $@ -> $?"

tests/scripts/all.sh

@@ -213,7 +213,7 @@ scripts/config.pl unset POLARSSL_THREADING_PTHREAD
 scripts/config.pl unset POLARSSL_THREADING_C
 scripts/config.pl unset POLARSSL_MEMORY_BACKTRACE # execinfo.h
 scripts/config.pl unset POLARSSL_MEMORY_BUFFER_ALLOC_C # calls exit
-CC=armcc WARNING_CFLAGS= make lib 2> armcc.stderr
+CC=armcc AR=armar WARNING_CFLAGS= make lib 2> armcc.stderr
 if [ -s armcc.stderr ]; then
     cat armcc.stderr
     exit 1;