ICU-22450 Disable the type_info workaround on newer versions of libst…

…dc++

The workaround for http://llvm.org/bugs/show_bug.cgi?id=13364 is related
to an ancient version of libstdc++ (4.6). On the flip side, with more recent
versions of GCC, the workaround can cause problems under some
conditions.

The _GLIBCXX_RELEASE macro was introduced in libstdc++ 7, checking for
it not being defined to enable the workaround makes it disabled with
libstdc++ >= 7, which don't need the workaround in the first place.

icu4c/source/common/unicode/std_string.h

@@ -31,7 +31,7 @@
 
 // Workaround for a libstdc++ bug before libstdc++4.6 (2011).
 // https://bugs.llvm.org/show_bug.cgi?id=13364
-#if defined(__GLIBCXX__)
+#if defined(__GLIBCXX__) && !defined(_GLIBCXX_RELEASE)
 namespace std { class type_info; }
 #endif
 #include <string>

icu4c/source/common/utypeinfo.h

@@ -24,7 +24,7 @@
 #include <exception>
 using std::exception;
 #endif
-#if defined(__GLIBCXX__)
+#if defined(__GLIBCXX__) && !defined(_GLIBCXX_RELEASE)
 namespace std { class type_info; } // WORKAROUND: http://llvm.org/bugs/show_bug.cgi?id=13364
 #endif
 #include <typeinfo>  // for 'typeid' to work

icu4c/source/io/unicode/ustream.h

@@ -34,7 +34,7 @@
  * C++ I/O stream API.
  */
 
-#if defined(__GLIBCXX__)
+#if defined(__GLIBCXX__) && !defined(_GLIBCXX_RELEASE)
 namespace std { class type_info; } // WORKAROUND: http://llvm.org/bugs/show_bug.cgi?id=13364
 #endif
 

icu4c/source/test/intltest/dcfmtest.cpp

@@ -31,7 +31,7 @@
 #include <string.h>
 #include <stdio.h>
 
-#if defined(__GLIBCXX__)
+#if defined(__GLIBCXX__) && !defined(_GLIBCXX_RELEASE)
 namespace std { class type_info; } // WORKAROUND: http://llvm.org/bugs/show_bug.cgi?id=13364
 #endif