- Remove duplicate dependency libxml2

- Remove comment about use_system_icu because icu is already unbundled
- Update pkg-message for the hanging tabs problem

MFH:		2018Q2 (blanket)

www/iridium/Makefile

@@ -53,7 +53,6 @@ LIB_DEPENDS=	libspeechd.so:accessibility/speech-dispatcher \
 		libgnome-keyring.so:security/libgnome-keyring \
 		libnss3.so:security/nss \
 		libexpat.so:textproc/expat2 \
-		libxml2.so:textproc/libxml2 \
 		libfontconfig.so:x11-fonts/fontconfig
 
 RUN_DEPENDS=	xdg-open:devel/xdg-utils \
@@ -100,7 +99,7 @@ GN_ARGS+=	clang_use_chrome_plugins=false \
 		use_system_libjpeg=true \
 		use_system_sqlite=false   # chrome has additional patches
 # TODO: investigate building with these options:
-# use_system_icu use_system_harfbuzz use_system_minigbm
+# use_system_harfbuzz use_system_minigbm
 GN_BOOTSTRAP_FLAGS=	--no-clean --no-rebuild
 
 SUB_FILES=	iridium-browser.desktop iridium

www/iridium/pkg-message

@@ -1,7 +1,8 @@
+--I--
 For correct operation, shared memory support has to be enabled
 in Iridium by performing the following command as root :
 
-sysctl kern.ipc.shm_allow_removed=1
+# sysctl kern.ipc.shm_allow_removed=1
 
 To preserve this setting across reboots, append the following
 to /etc/sysctl.conf :
@@ -9,3 +10,14 @@ to /etc/sysctl.conf :
 kern.ipc.shm_allow_removed=1
 
 FreeBSD 11.0-R and newer have this set by default.
+
+--II--
+Iridium has a known problem of hanging tabs. The workaround
+for this problem is to mount ~/.cache/iridium as memory-fs.
+In order to do this, before you run iridium, please run these
+commands once as root for each user who uses iridium (replace
+{user}/{group} with your user/group names):
+
+# [ -d ~{user}/.cache/iridium ] || mkdir ~{user}/.cache/iridium
+# echo "md $(echo ~{user})/.cache/iridium mfs rw,late,-w{user}:{group},-s300m 2 0" >> /etc/fstab
+# mount ~{user}/.cache/iridium