Fix the default timezone detection in ICU....

third_party/icu/patches/linuxtz3.patch

Index: third_party/icu/patches/linuxtz3.patch
===================================================================
--- third_party/icu/patches/linuxtz3.patch	(revision 0)
+++ third_party/icu/patches/linuxtz3.patch	(revision 0)
@@ -0,0 +1,74 @@
+Index: source/common/putil.c
+===================================================================
+--- source/common/putil.c	(revision 60495)
++++ source/common/putil.c	(working copy)
+@@ -661,6 +661,26 @@
+         || uprv_strcmp(id, "CST6CDT") == 0
+         || uprv_strcmp(id, "EST5EDT") == 0);
+ }
++
++/* On some Unix-like OS, 'posix' subdirectory in
++   /usr/share/zoneinfo replicates the top-level contents. 'right'
++   subdirectory has the same set of files, but individual files
++   are different from those in the top-level directory or 'posix'
++   because 'right' has files for TAI (Int'l Atomic Time) while 'posix'
++   has files for UTC.
++   When the first match for /etc/localtime is in either of them
++   (usually in posix because 'right' has different file contents),
++   or TZ environment variable points to one of them, createTimeZone
++   fails because, say, 'posix/America/New_York' is not an Olson
++   timezone id ('America/New_York' is). So, we have to remove
++   'posix/' and 'right/' at the beginning. */
++static void removeZoneIDPrefix(const char** id) {

[Evan Martin, 2010/10/08 22:00:14]

"skip" might be a better verb than "remove", as the latter indicates that it's
modifying the argument, but you're just advancing the pointer here.

++    if (uprv_strncmp(*id, "posix/", 6) == 0
++        || uprv_strncmp(*id, "right/", 6) == 0)
++    {
++        *id += 6;
++    }
++}
+ #endif
+ 
+ #if defined(U_TZNAME) && !defined(U_WINDOWS)
+@@ -869,11 +889,12 @@
+ 
+     /* Check each entry in the directory. */
+     while((dirEntry = readdir(dirp)) != NULL) {
+-        if (uprv_strcmp(dirEntry->d_name, SKIP1) != 0 && uprv_strcmp(dirEntry->d_name, SKIP2) != 0) {
++        const char* dirName = dirEntry->d_name;
++        if (uprv_strcmp(dirName, SKIP1) != 0 && uprv_strcmp(dirName, SKIP2) != 0) {
+             /* Create a newpath with the new entry to test each entry in the directory. */
+             char newpath[MAX_PATH_SIZE];
+             uprv_strcpy(newpath, curpath);
+-            uprv_strcat(newpath, dirEntry->d_name);
++            uprv_strcat(newpath, dirName);
+ 
+             if ((subDirp = opendir(newpath)) != NULL) {
+                 /* If this new path is a directory, make a recursive call with the newpath. */
+@@ -890,9 +911,11 @@
+                 */
+                 if (result != NULL)
+                     break;
+-            } else if (uprv_strcmp(TZFILE_SKIP, dirEntry->d_name) != 0 && uprv_strcmp(TZFILE_SKIP2, dirEntry->d_name) != 0) {
++            } else if (uprv_strcmp(TZFILE_SKIP, dirName) != 0 && uprv_strcmp(TZFILE_SKIP2, dirName) != 0) {
+                 if(compareBinaryFiles(TZDEFAULT, newpath, tzInfo)) {
+-                    uprv_strcpy(SEARCH_TZFILE_RESULT, newpath + (sizeof(TZZONEINFO) - 1));
++                    const char* zoneid = newpath + (sizeof(TZZONEINFO)) - 1;
++                    removeZoneIDPrefix(&zoneid);
++                    uprv_strcpy(SEARCH_TZFILE_RESULT, zoneid);
+                     result = SEARCH_TZFILE_RESULT;
+                     /* Get out after the first one found. */
+                     break;
+@@ -931,12 +954,7 @@
+     if (tzid != NULL && isValidOlsonID(tzid))
+     {
+         /* This might be a good Olson ID. */
+-        if (uprv_strncmp(tzid, "posix/", 6) == 0
+-            || uprv_strncmp(tzid, "right/", 6) == 0)
+-        {
+-            /* Remove the posix/ or right/ prefix. */
+-            tzid += 6;
+-        }
++        removeZoneIDPrefix(&tzid);
+         return tzid;
+     }
+     /* else U_TZNAME will give a better result. */