我在这里使用 cabal 来安装 package c2hs。但是，它需要快乐，所以我安装happy了cabal install happy.
之后，在尝试安装时c2hs，language-c我都package happy not found上了。
这是终端日志：
~> cabal install happy
Resolving dependencies...
[1 of 1] Compiling Main ( /tmp/happy-1.18.9-12936/happy-1.18.9/Setup.lhs, /tmp/happy-1.18.9-12936/happy-1.18.9/dist/setup/Main.o )
/tmp/happy-1.18.9-12936/happy-1.18.9/Setup.lhs:6:52:
Warning: In the use of `buildVerbose'
(imported from Distribution.Simple.Setup):
Deprecated: "Use buildVerbosity instead"
/tmp/happy-1.18.9-12936/happy-1.18.9/Setup.lhs:7:52:
Warning: In the use of `defaultUserHooks'
(imported from Distribution.Simple):
Deprecated: "Use simpleUserHooks or autoconfUserHooks, unless you need Cabal-1.2
compatibility in which case you must stick with defaultUserHooks"
/tmp/happy-1.18.9-12936/happy-1.18.9/Setup.lhs:12:26:
Warning: In the use of `try'
(imported from System.IO.Error):
Deprecated: "Please use the new exceptions variant, Control.Exception.try"
Linking /tmp/happy-1.18.9-12936/happy-1.18.9/dist/setup/setup ...
Warning: defaultUserHooks in Setup script is deprecated.
Configuring happy-1.18.9...
Building happy-1.18.9...
Preprocessing executable 'happy' for happy-1.18.9...
[ 1 of 18] Compiling NameSet ( src/NameSet.hs, dist/build/happy/happy-tmp/NameSet.o )
[ 2 of 18] Compiling Target ( src/Target.lhs, dist/build/happy/happy-tmp/Target.o )
[ 3 of 18] Compiling AbsSyn ( src/AbsSyn.lhs, dist/build/happy/happy-tmp/AbsSyn.o )
[ 4 of 18] Compiling ParamRules ( src/ParamRules.hs, dist/build/happy/happy-tmp/ParamRules.o )
[ 5 of 18] Compiling GenUtils ( src/GenUtils.lhs, dist/build/happy/happy-tmp/GenUtils.o )
[ 6 of 18] Compiling ParseMonad ( src/ParseMonad.lhs, dist/build/happy/happy-tmp/ParseMonad.o )
[ 7 of 18] Compiling Lexer ( src/Lexer.lhs, dist/build/happy/happy-tmp/Lexer.o )
[ 8 of 18] Compiling Parser ( dist/build/happy/happy-tmp/Parser.hs, dist/build/happy/happy-tmp/Parser.o )
[ 9 of 18] Compiling AttrGrammar ( src/AttrGrammar.lhs, dist/build/happy/happy-tmp/AttrGrammar.o )
[10 of 18] Compiling AttrGrammarParser ( dist/build/happy/happy-tmp/AttrGrammarParser.hs, dist/build/happy/happy-tmp/AttrGrammarParser.o )
[11 of 18] Compiling Grammar ( src/Grammar.lhs, dist/build/happy/happy-tmp/Grammar.o )
[12 of 18] Compiling First ( src/First.lhs, dist/build/happy/happy-tmp/First.o )
[13 of 18] Compiling LALR ( src/LALR.lhs, dist/build/happy/happy-tmp/LALR.o )
[14 of 18] Compiling Paths_happy ( dist/build/autogen/Paths_happy.hs, dist/build/happy/happy-tmp/Paths_happy.o )
[15 of 18] Compiling ProduceCode ( src/ProduceCode.lhs, dist/build/happy/happy-tmp/ProduceCode.o )
[16 of 18] Compiling ProduceGLRCode ( src/ProduceGLRCode.lhs, dist/build/happy/happy-tmp/ProduceGLRCode.o )
[17 of 18] Compiling Info ( src/Info.lhs, dist/build/happy/happy-tmp/Info.o )
[18 of 18] Compiling Main ( src/Main.lhs, dist/build/happy/happy-tmp/Main.o )
Linking dist/build/happy/happy ...
Installing executable(s) in /home/david/.cabal/bin
~> cabal install c2hs
Resolving dependencies...
Configuring language-c-0.3.2.1...
cabal: The program happy is required but it could not be found.
cabal: Error: some packages failed to install:
c2hs-0.16.3 depends on language-c-0.3.2.1 which failed to install.
language-c-0.3.2.1 failed during the configure step. The exception was:
ExitFailure 1
exit 1
~> cabal install language-c
Resolving dependencies...
Configuring language-c-0.4.2...
cabal: The program happy is required but it could not be found.
cabal: Error: some packages failed to install:
language-c-0.4.2 failed during the configure step. The exception was:
ExitFailure 1
exit 1
~>
有任何想法吗？谢谢你。