支持win64的modelsim,questasim的gcc编译器
在modelsim出现下列提示时解压到安装目录使用
# 2019.2
# do run.do
# Please download and install gcc-4.5.0-mingw64vc12.zip from the Mentor ftp site.
# Using cygwin gcc is not supported.
gcc-4.8.0 gcc-4.9.0 gcc-5.1.0 gcc-6.1.0 gcc-7.1.0 gcc-8.1.0 gcc-9.1.0.7z 已验证可用，请放心下载。GCC used to stand for the GNU C Compiler, but since the compiler supports several other languages aside from C, it now stands for the GNU Compiler Collection.
