Fix NaCl builds for *BSD

From what I see there is a difference between *BSD and Linux when
linking vs. toxcore which has been bulit vs. the NaCl library:

on Linux it only links if NaCl's object files (i.e. randombytes.o) is
present in the linker options, however on *BSD systems this will cause a
linking error, see:
https://github.com/Tox/toxic/issues/31#issuecomment-38224441

This commit makes sure that we do not add the NaCl object files to our
pkg-config settings on *BSD, but do add them on Linux.

configure.ac

@@ -38,6 +38,7 @@ NCURSES_FOUND="no"
 LIBCONFIG_FOUND="no"
 LIBCHECK_FOUND="no"
 WANT_NACL="no"
+ADD_NACL_OBJECTS_TO_PKGCONFIG="yes"
 
 TOXCORE_LT_LDFLAGS="-version-info $LIBTOXCORE_LT_VERSION"
 TOXAV_LT_LDFLAGS="-version-info $LIBTOXAV_LT_VERSION"
@@ -233,6 +234,7 @@ case $host_os in
         LDFLAGS="$LDFLAGS -L/usr/local/lib"
         CFLAGS="$CFLAGS -I/usr/local/include"
         CPPFLAGS="$CPPFLAGS -I/usr/local/include"
+        ADD_NACL_OBJECTS_TO_PKGCONFIG="no"
     ;;
 esac
 AM_CONDITIONAL(WIN32, test "x$WIN32" = "xyes")
@@ -244,6 +246,8 @@ AC_SUBST(EXTRA_LT_LDFLAGS)
 if test "x$WANT_NACL" = "xyes"; then
     NACL_LIBS=
     NACL_LDFLAGS=
+    NACL_OBJECTS=
+    NACL_OBJECTS_PKGCONFIG=
     LDFLAGS_SAVE="$LDFLAGS"
     if test -n "$NACL_SEARCH_LIBS"; then
         LDFLAGS="-L$NACL_SEARCH_LIBS $LDFLAGS"
@@ -267,14 +271,19 @@ if test "x$WANT_NACL" = "xyes"; then
 
     if (test -f "$NACL_SEARCH_LIBS/cpucycles.o") &&
        (test -f "$NACL_SEARCH_LIBS/randombytes.o"); then
-        NACL_LIBS="$NACL_LIBS $NACL_SEARCH_LIBS/cpucycles.o $NACL_SEARCH_LIBS/randombytes.o"
+        NACL_OBJECTS="$NACL_SEARCH_LIBS/cpucycles.o $NACL_SEARCH_LIBS/randombytes.o"
+        if test "x$ADD_NACL_OBJECTS_TO_PKGCONFIG" = "xyes"; then
+            NACL_OBJECTS_PKGCONFIG="$NACL_OBJECTS"
+        fi
     else
-        AC_MSG_ERROR([nacl weirdness: required object files cpucycles.o randombytes.o not found])
+        AC_MSG_ERROR([required NaCl object files cpucycles.o randombytes.o not found, please specify their location using the --with-nacl-libs parameter])
     fi
 
     LDFLAGS="$LDFLAGS_SAVE"
     AC_SUBST(NACL_LIBS)
     AC_SUBST(NACL_LDFLAGS)
+    AC_SUBST(NACL_OBJECTS)
+    AC_SUBST(NACL_OBJECTS_PKGCONFIG)
 else
     LIBSODIUM_LIBS=
     LIBSODIUM_LDFLAGS=

libtoxcore.pc.in

@@ -7,5 +7,5 @@ Name: libtoxcore
 Description: Tox protocol library
 Requires:
 Version: @PACKAGE_VERSION@
-Libs: -L${libdir} @NACL_LDFLAGS@ -ltoxcore @NACL_LIBS@ @LIBS@
+Libs: @NACL_OBJECTS_PKGCONFIG@ -L${libdir} @NACL_LDFLAGS@ -ltoxcore @NACL_LIBS@ @LIBS@
 Cflags: -I${includedir}

other/Makefile.inc

@@ -12,6 +12,7 @@ DHT_bootstrap_LDADD =   $(LIBSODIUM_LDFLAGS) \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 

testing/Makefile.inc

@@ -36,6 +36,7 @@ DHT_test_LDADD =        $(LIBSODIUM_LDFLAGS) \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 
@@ -52,6 +53,7 @@ Lossless_UDP_testclient_LDADD = \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 
@@ -68,6 +70,7 @@ Lossless_UDP_testserver_LDADD = \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 
@@ -82,6 +85,7 @@ Messenger_test_LDADD =  $(LIBSODIUM_LDFLAGS) \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 
@@ -98,6 +102,7 @@ crypto_speed_test_LDADD = \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 
@@ -114,6 +119,7 @@ tox_sync_LDADD =        $(LIBSODIUM_LDFLAGS) \
                         $(NACL_LDFLAGS) \
                         libtoxcore.la \
                         $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NACL_LIBS) \
                         $(WINSOCK2_LIBS)
 endif

toxcore/Makefile.inc

@@ -49,4 +49,5 @@ libtoxcore_la_LDFLAGS = $(TOXCORE_LT_LDFLAGS) \
                         $(WINSOCK2_LIBS)
 
 libtoxcore_la_LIBADD =  $(LIBSODIUM_LIBS) \
+                        $(NACL_OBJECTS) \
                         $(NAC_LIBS)