[PATCH] libtool: fix data imports with GNU ld on 64bit windows

Using '_nm__' to match symbols from GNU ld to enable special data import
treatment on windows targets does rely on the leading underscore being
stripped from the __nm_ prefix rather than the subsequent symbol name.
This does fail on 64bit Windows targets, because there is no leading
underscore with symbol names any more.

* m4/libtool.m4 (lt_cv_sys_global_symbol_pipe): Strip the leading
underscore, if any, from the symbol name that follows the optional
__imp_ or __nm_ prefix, rather than from that prefix.
* build-aux/ltmain.in (func_generate_dlsyms): Account for the global
symbol pipe leaving the __nm_ prefix intact now, but stripping the
leading underscore, if any, from the subsequent symbol name instead.
---
 build-aux/ltmain.in | 2 +-
 m4/libtool.m4       | 9 +++++++--
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/build-aux/ltmain.in b/build-aux/ltmain.in
index 96b37003..ad154fb8 100644
--- a/build-aux/ltmain.in
+++ b/build-aux/ltmain.in
@@ -2810,7 +2810,7 @@ extern \"C\" {
 	          fi
 	          func_to_tool_file "$dlprefile" func_convert_file_msys_to_w32
 	          eval "$NM \"$func_to_tool_file_result\" 2>/dev/null | $global_symbol_pipe |
-	            $SED -e '/I __imp/d' -e 's/I __nm_/D /;s/_nm__//' >> '$nlist'"
+	            $SED -e '/I __imp/d' -e 's/I __nm_/D /;s/ __nm_/ /' >> '$nlist'"
 	        }
 	      else # not an import lib
 	        $opt_dry_run || {
diff --git a/m4/libtool.m4 b/m4/libtool.m4
index 416ff1cc..05bf608c 100644
--- a/m4/libtool.m4
+++ b/m4/libtool.m4
@@ -4026,7 +4026,12 @@ esac
 for ac_symprfx in "" "_"; do
 
   # Transform symcode, sympat, and symprfx into a raw symbol and a C symbol.
-  symxfrm="\\1 $ac_symprfx\\2 \\2"
+  # In Windows import libraries, symbols may be prefixed with __imp_, as well
+  # as __nm_ when using GNU ld.  The leading underscore (in 32bit) comes after
+  # the __imp_ and __nm_ prefix, so make sure to strip the underscore from the
+  # symbol name instead of the __imp_ or __nm_ prefix, leaving these prefixes
+  # intact in the symbol pipe output.
+  symxfrm="\\1 \\2$ac_symprfx\\3 \\2\\3"
 
   # Write the raw and C identifiers.
   if test "$lt_cv_nm_interface" = "MS dumpbin"; then
@@ -4052,7 +4057,7 @@ for ac_symprfx in "" "_"; do
 "     s[1]~prfx {split(s[1],t,\"@\"); print f,t[1],substr(t[1],length(prfx))}"\
 "     ' prfx=^$ac_symprfx]"
   else
-    lt_cv_sys_global_symbol_pipe="sed -n -e 's/^.*[[	 ]]\($symcode$symcode*\)[[	 ]][[	 ]]*$ac_symprfx$sympat$opt_cr$/$symxfrm/p'"
+    lt_cv_sys_global_symbol_pipe="sed -n -e 's/^.*[[	 ]]\($symcode$symcode*\)[[	 ]][[	 ]]*\(__imp_\|__nm_\)\{0,1\}$ac_symprfx$sympat$opt_cr$/$symxfrm/p'"
   fi
   lt_cv_sys_global_symbol_pipe="$lt_cv_sys_global_symbol_pipe | sed '/ __gnu_lto/d'"
 
-- 
2.22.0