hunspell: MSVC debug runtime iterators don't want to decrement past begin()

Change-Id: I258dc551d14ba72113b284be3566ba924434ab4c

external/hunspell/UnpackedTarball_hunspell.mk

@@ -13,6 +13,7 @@ $(eval $(call gb_UnpackedTarball_set_tarball,hunspell,$(HUNSPELL_TARBALL)))
 
 $(eval $(call gb_UnpackedTarball_add_patches,hunspell,\
 	external/hunspell/hunspell-solaris.patch \
+	external/hunspell/hunspell-iterator.patch.1 \
 ))
 
 ifeq ($(COM),MSC)

external/hunspell/hunspell-iterator.patch.1

+MSVC debug runtime iterators don't want to be decremented past begin()
+
+--- hunspell/src/hunspell/affixmgr.cxx.orig	2016-04-15 23:30:37.555875079 +0200
++++ hunspell/src/hunspell/affixmgr.cxx	2016-04-15 23:30:43.669875027 +0200
+@@ -4638,7 +4638,7 @@
+       return;
+ 
+   int neg = 0;
+-  for (std::string::iterator k = piece.begin() + piece.size() - 1; k >= piece.begin(); --k) {
++  for (std::string::iterator k = piece.begin() + piece.size() - 1; ; --k) {
+     switch (*k) {
+       case '[': {
+         if (neg)
+@@ -4666,6 +4666,8 @@
+           *(k + 1) = *k;
+       }
+     }
++    if (k == piece.begin())
++        break;
+   }
+ }
+