Execute POSIX behavior not just on Solaris but all POSIX platforms.

References: https://bugzilla.opensuse.org/1162882
---
 source/common/putil.cpp |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: icu/source/common/putil.cpp
===================================================================
--- icu.orig/source/common/putil.cpp
+++ icu/source/common/putil.cpp
@@ -1607,7 +1607,7 @@ static const char *uprv_getPOSIXIDForCat
             /* Solaris speaks POSIX -  See IEEE Std 1003.1-2008
              * This is needed to properly handle empty env. variables
              */
-#if U_PLATFORM == U_PF_SOLARIS
+#if U_PLATFORM_IMPLEMENTS_POSIX
             if ((posixID == 0) || (posixID[0] == '\0')) {
                 posixID = getenv(category == LC_MESSAGES ? "LC_MESSAGES" : "LC_CTYPE");
                 if ((posixID == 0) || (posixID[0] == '\0')) {