我正在MacOS Catalina 10.15.4上运行。我已经成功安装了各种红宝石宝石，但是在安装Gosu时出现此错误（“ sudo gem install gosu”）
current directory: /usr/local/lib/ruby/gems/2.7.0/gems/gosu-0.15.1/ext/gosu
make "DESTDIR="
compiling ../../src/Audio.cpp
In file included from ../../src/Audio.cpp:1:
In file included from ../../src/AudioImpl.hpp:3:
In file included from ../../Gosu/Audio.hpp:7:
In file included from ../../Gosu/IO.hpp:6:
In file included from ../../Gosu/Platform.hpp:20:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/algorithm:641:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstring:60:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/string.h:60:15: fatal error: 'string.h' file not found
#include_next <string.h>
^~~~~~~~~~
1 error generated.
make: *** [Audio.o] Error 1
请帮助。非常感谢。