gsmopen: compile on windows, with iconv for windows

diff --git a/src/mod/endpoints/mod_gsmopen/win_iconv.c b/src/mod/endpoints/mod_gsmopen/win_iconv.c
deleted file mode 120000 (symlink)
index 98b5c9e..0000000
--- a/src/mod/endpoints/mod_gsmopen/win_iconv.c
+++ /dev/null
@@ -1 +0,0 @@
-win_iconv/win_iconv.c
\ No newline at end of file