Re: [patch] Default to --enable-libstdcxx-time=auto

[Jonathan Wakely]

        * src/c++11/compatibility-chrono.cc (steady_clock::now()): If
        !_GLIBCXX_USE_GETTIMEOFDAY perform conversion inline instead of
        calling non-existent from_time_t.

Tested x86_64-linux, committed to trunk and the 4.8 branch.

Steve, trunk should build OK now, thanks for testing and reporting it.

commit 024a5d2b1618f46c950bf3d43b5dcb7a3e019ff7
Author: Jonathan Wakely <jwakely....@gmail.com>
Date:   Tue May 28 20:46:06 2013 +0100

        * src/c++11/compatibility-chrono.cc (steady_clock::now()): If
        !_GLIBCXX_USE_GETTIMEOFDAY perform conversion inline instead of
        calling non-existent from_time_t.

diff --git a/libstdc++-v3/src/c++11/compatibility-chrono.cc 
b/libstdc++-v3/src/c++11/compatibility-chrono.cc
index fd67dae..efc32f5 100644
--- a/libstdc++-v3/src/c++11/compatibility-chrono.cc
+++ b/libstdc++-v3/src/c++11/compatibility-chrono.cc
@@ -78,7 +78,10 @@ namespace std _GLIBCXX_VISIBILITY(default)
                                 + chrono::microseconds(tv.tv_usec)));
 #else
       std::time_t __sec = std::time(0);
-      return system_clock::from_time_t(__sec);
+      // This is the conversion done by system_clock::from_time_t(__sec)
+      typedef chrono::time_point<system_clock, seconds>        __from;
+      return time_point_cast<system_clock::duration>
+            (__from(chrono::seconds(__sec)));
 #endif
     }