最新版のMinGW (GCC 4.6.1)では、"-mno-cygwin"フラグを使用するとエラーになり、コンパイルに失敗する。
Makefileを修正して、"-mno-cygwin"フラグを取り除くとコンパイル可能。
This was reported in a japanese community.
Latest MinGW (GCC 4.6.1) doesn't recognize "-mno-cygwin" flag anymore, it will cause compiling error.
cc1: error: unrecognized command line option "-mno-cygwin"
Easy workaround is to remove "-mno-cygwin" flag from Makefile.
But it might cause problem for the people who use older cygwin.
Three of Makefile - simutrans, makeobj, nettools - contain this flag.