autogen.sh: fix out-of-tree module Makefiles for Win32 make

These were created as symlinks, which doesn't work with Win32 make as it
doesn't understand Cygwin symlinks.

Instead, create them as actual files.

Note: the reason why they work as symlinks at all is that the Makefile
uses $(realpath) and partial_build.mk does not, so they can
resolve relative paths from 2 different directories...

Change-Id: I4a9abffae82561111a9525fb35ed4b174cc8d96a
Reviewed-on: https://gerrit.libreoffice.org/56691
Tested-by: Jenkins
Reviewed-by: Thorsten Behrens <Thorsten.Behrens@CIB.de>

autogen.sh

@@ -165,12 +165,18 @@ if ($src_path ne $build_path)
 {
     system ("ln -sf $src_path/configure.ac configure.ac");
     system ("ln -sf $src_path/g g");
+    my $src_path_win=$src_path;
+    if ($system =~ /CYGWIN.*/) {
+        $src_path_win=`cygpath -m $src_path`;
+        chomp $src_path_win;
+    }
     my @modules = <$src_path/*/Makefile>;
     foreach my $module (@modules)
     {
         my $dir = basename (dirname ($module));
         mkdir ($dir);
-        system ("ln -sf $src_path/$dir/Makefile $dir/Makefile");
+        system ("rm $dir/Makefile");
+        system ("printf 'module_directory:=$src_path_win/$dir/\ninclude \$(module_directory)/../solenv/gbuild/partial_build.mk\n' > $dir/Makefile");
     }
     my @external_modules = <$src_path/external/*/Makefile>;
     mkdir ("external");
@@ -179,7 +185,8 @@ if ($src_path ne $build_path)
     {
         my $dir = basename (dirname ($module));
         mkdir ("external/$dir");
-        system ("ln -sf $src_path/external/$dir/Makefile external/$dir/Makefile");
+        system ("rm external/$dir/Makefile");
+        system ("printf 'module_directory:=$src_path_win/external/$dir/\ninclude \$(module_directory)/../../solenv/gbuild/partial_build.mk\n' > external/$dir/Makefile");
     }
 }
 system ("$aclocal $aclocal_flags") && die "Failed to run aclocal";