This patch removes the usage of tolower() in fts code, which is not locale
neutral and causes problem in some locales such as Turkish.
See http://crbug.com/15261 for details.
An upstream ticket was also created for this issue:
http://www.sqlite.org/src/tktview/991789d9f3136a0460dc83a33e815c1aa9757c26

Index: ext/fts3/fts3.c
===================================================================
--- ext/fts3/fts3.c	(revision 24387)
+++ ext/fts3/fts3.c	(working copy)
@@ -330,7 +330,7 @@
   return (c&0x80)==0 ? isspace(c) : 0;
 }
 static int safe_tolower(char c){
-  return (c&0x80)==0 ? tolower(c) : c;
+  return (c>='A' && c<='Z') ? (c-'A'+'a') : c;
 }
 static int safe_isalnum(char c){
   return (c&0x80)==0 ? isalnum(c) : 0;
Index: ext/fts3/fts3_tokenizer1.c
===================================================================
--- ext/fts3/fts3_tokenizer1.c	(revision 24387)
+++ ext/fts3/fts3_tokenizer1.c	(working copy)
@@ -191,7 +191,7 @@
         ** case-insensitivity.
         */
         unsigned char ch = p[iStartOffset+i];
-        c->pToken[i] = ch<0x80 ? tolower(ch) : ch;
+        c->pToken[i] = (ch>='A' && ch<='Z') ? (ch-'A'+'a') : ch;
       }
       *ppToken = c->pToken;
       *pnBytes = n;
Index: ext/fts1/simple_tokenizer.c
===================================================================
--- ext/fts1/simple_tokenizer.c	(revision 24387)
+++ ext/fts1/simple_tokenizer.c	(working copy)
@@ -138,7 +138,7 @@
         ** case-insensitivity.
         */
         char ch = c->pCurrent[ii];
-        c->zToken[ii] = (unsigned char)ch<0x80 ? tolower(ch) : ch;
+        c->zToken[ii] = ((ch>='A' && ch<='Z') ? (ch-'A'+'a') : ch);
       }
       c->zToken[n] = '\0';
       *ppToken = c->zToken;
Index: ext/fts1/fts1_tokenizer1.c
===================================================================
--- ext/fts1/fts1_tokenizer1.c	(revision 24387)
+++ ext/fts1/fts1_tokenizer1.c	(working copy)
@@ -182,7 +182,7 @@
         ** case-insensitivity.
         */
         unsigned char ch = p[iStartOffset+i];
-        c->pToken[i] = ch<0x80 ? tolower(ch) : ch;
+        c->pToken[i] = (ch>='A' && ch<='Z') ? (ch-'A'+'a') : ch;
       }
       *ppToken = c->pToken;
       *pnBytes = n;
Index: ext/fts1/fts1.c
===================================================================
--- ext/fts1/fts1.c	(revision 24387)
+++ ext/fts1/fts1.c	(working copy)
@@ -208,7 +208,7 @@
   return (c&0x80)==0 ? isspace(c) : 0;
 }
 static int safe_tolower(char c){
-  return (c&0x80)==0 ? tolower(c) : c;
+  return (c>='A' && c<='Z') ? (c-'A'+'a') : c;
 }
 static int safe_isalnum(char c){
   return (c&0x80)==0 ? isalnum(c) : 0;
Index: ext/fts2/fts2.c
===================================================================
--- ext/fts2/fts2.c	(revision 24387)
+++ ext/fts2/fts2.c	(working copy)
@@ -372,7 +372,7 @@
   return (c&0x80)==0 ? isspace(c) : 0;
 }
 static int safe_tolower(char c){
-  return (c&0x80)==0 ? tolower(c) : c;
+  return (c>='A' && c<='Z') ? (c-'A'+'a') : c;
 }
 static int safe_isalnum(char c){
   return (c&0x80)==0 ? isalnum(c) : 0;
Index: ext/fts2/fts2_tokenizer1.c
===================================================================
--- ext/fts2/fts2_tokenizer1.c	(revision 24387)
+++ ext/fts2/fts2_tokenizer1.c	(working copy)
@@ -191,7 +191,7 @@
         ** case-insensitivity.
         */
         unsigned char ch = p[iStartOffset+i];
-        c->pToken[i] = ch<0x80 ? tolower(ch) : ch;
+        c->pToken[i] = (ch>='A' && ch<='Z') ? (ch-'A'+'a') : ch;
       }
       *ppToken = c->pToken;
       *pnBytes = n;