[PATCH] Fix undefined references seen with mingw-w64

[Jonathan Wakely]

        * config/abi/pre/gnu.ver: Add missing exports for mingw.

Tested x86_64-linux and x86_64-w64-mingw32, committed to trunk.



commit 8a70204f5e3cfcea0e2a0d5404bf547bc8da7bcc
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Thu Aug 30 13:25:36 2018 +0100

    Fix undefined references seen with mingw-w64
    
            * config/abi/pre/gnu.ver: Add missing exports for mingw.

diff --git a/libstdc++-v3/config/abi/pre/gnu.ver 
b/libstdc++-v3/config/abi/pre/gnu.ver
index 03b23200a1a..4766d28f708 100644
--- a/libstdc++-v3/config/abi/pre/gnu.ver
+++ b/libstdc++-v3/config/abi/pre/gnu.ver
@@ -2049,6 +2049,11 @@ GLIBCXX_3.4.26 {
     # std::__throw_ios_failure(const char*, int);
     _ZSt19__throw_ios_failurePKci;
 
+    # std::wistream::ignore(long long, unsigned short)
+    _ZNSt13basic_istreamIwSt11char_traitsIwEE6ignoreExt;
+    # std::basic_filebuf::open(const wchar_t*, openmode)
+    _ZNSt13basic_filebufI[cw]St11char_traitsI[cw]EE4openEPKwSt13_Ios_Openmode;
+
 } GLIBCXX_3.4.25;
 
 # Symbols in the support library (libsupc++) have their own tag.