Gross hack to make libtool work with gcc-wrapper - frontended
link.exe on Windows. Make libtool ignore all libs & simply pass
them on as-is to the linker

A proper fix would be to make gcc-wrapper behave like gcc during
linking, by accepting cygwin path names, and correctly expanding
-l<short_lib_name> to lib<short_lib_name>.lib

diff -ur gpgmepp.org/m4/libtool.m4 gpgmepp/m4/libtool.m4
--- gpgmepp.org/m4/libtool.m4	2016-11-16 13:20:16.000000000 +0100
+++ gpgmepp/m4/libtool.m4	2017-11-21 22:00:05.006587800 +0100
@@ -3230,24 +3230,11 @@
   ;;
 
 cygwin*)
-  # func_win32_libid is a shell function defined in ltmain.sh
-  lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
-  lt_cv_file_magic_cmd='func_win32_libid'
+  lt_cv_deplibs_check_method=pass_all
   ;;
 
 mingw* | pw32*)
-  # Base MSYS/MinGW do not provide the 'file' command needed by
-  # func_win32_libid shell function, so use a weaker test based on 'objdump',
-  # unless we find 'file', for example because we are cross-compiling.
-  # func_win32_libid assumes BSD nm, so disallow it if using MS dumpbin.
-  if ( test "$lt_cv_nm_interface" = "BSD nm" && file / ) >/dev/null 2>&1; then
-    lt_cv_deplibs_check_method='file_magic ^x86 archive import|^x86 DLL'
-    lt_cv_file_magic_cmd='func_win32_libid'
-  else
-    # Keep this pattern in sync with the one in func_win32_libid.
-    lt_cv_deplibs_check_method='file_magic file format (pei*-i386(.*architecture: i386)?|pe-arm-wince|pe-x86-64)'
-    lt_cv_file_magic_cmd='$OBJDUMP -f'
-  fi
+  lt_cv_deplibs_check_method=pass_all
   ;;
 
 cegcc*)