我做了：
cabal update
cabal install gtk2hs-buildtools
但卡在这里：
>cabal install gtk
Resolving dependencies...
[1 of 2] Compiling SetupWrapper ( C:\Users\1\AppData\Local\Temp\gtk-0.12.5.4
-4000\gtk-0.12.5.4\SetupWrapper.hs, C:\Users\1\AppData\Local\Temp\gtk-0.12.5.4-4
000\gtk-0.12.5.4\dist\setup\SetupWrapper.o )
[2 of 2] Compiling Main ( C:\Users\1\AppData\Local\Temp\gtk-0.12.5.4
-4000\gtk-0.12.5.4\Setup.hs, C:\Users\1\AppData\Local\Temp\gtk-0.12.5.4-4000\gtk
-0.12.5.4\dist\setup\Main.o )
Linking C:\Users\1\AppData\Local\Temp\gtk-0.12.5.4-4000\gtk-0.12.5.4\dist\setup\
setup.exe ...
[1 of 2] Compiling Gtk2HsSetup ( Gtk2HsSetup.hs, dist\setup-wrapper\Gtk2HsS
etup.o )
[2 of 2] Compiling Main ( SetupMain.hs, dist\setup-wrapper\Main.o )
Linking dist/setup-wrapper\setup.exe ...
Configuring gtk-0.12.5.4...
setup.exe: The pkg-config package gtk+-2.0 is required but it could not be
found.
Failed to install gtk-0.12.5.4
cabal: Error: some packages failed to install:
gtk-0.12.5.4 failed during the configure step. The exception was:
ExitFailure 1
但我在文件夹中有这样的文件C:\gtkallinone\bin：
libgthread-2.0-0.dll
并且C:\gtkallinone\lib：
gthread-2.0.lib
gthread-2.0.def
我在PATH环境中有这条路径：
C:\gtkallinone\bin
如何安装它？
*更新*
安装后gtk-0.12.5.4遇到了缺少的问题m.dll。
我用ghc-pkg uregister.
现在看到更新的答案。