[Agda] Agda and GHC 7.8

[Jan Stolarek]

I've got some help from #ghc. It seems that this might have something to do with CPP 
preprocessing. Calling `cabal install -v3` gives a lot more information. I see lots of calls to 
cpphs and the last one calls cpphs on Lexer.hs (sorry for weird line breaks):

*** C pre-processor:
cpphs -include 
dist/dist-sandbox-1828dee6/build/autogen/cabal_macros.h --cpp -Werror -Idist/dist-sandbox-1828dee6/build -I 
dist/dist-sandbox-1828dee6/build -I 
dist/dist-sandbox-1828dee6/build/autogen -Idist/dist-sandbox-1828dee6/build -I /dane/sandboxes/ghc/7.8.3//lib/g
hc-7.8.3/process-1.2.0.0/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/old-time-1.1.0.2/include -I /dane/download/agda/.cabal-sand
box/lib/x86_64-linux-ghc-7.8.3/vector-0.10.11.0/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/directory-1.2.1.0/include -I /dane/s
andboxes/ghc/7.8.3//lib/ghc-7.8.3/unix-2.7.0.1/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/bytestring-0.10.4.0/include -I /dane/
download/agda/.cabal-sandbox/lib/x86_64-linux-ghc-7.8.3/primitive-0.5.3.0/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/time-1.4.2
/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/base-4.7.0.1/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/integer-gmp-0.5.1.
0/include -I /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/include '-D__GLASGOW_HASKELL__=708' '-Dlinux_BUILD_OS=1' '-Dx86_64_BUILD_ARCH=1' '
-Dlinux_HOST_OS=1' '-Dx86_64_HOST_ARCH=1' '-D__SSE__=1' '-D__SSE2__=1' -x assembler-with-cpp 
dist/dist-sandbox-1828dee6/build/Agda/Syntax/Parser/Lexer.hs -o /tmp/ghc656_0/ghc656_51.hscpp
Warning: trailing characters after #if directive in 
file /dane/sandboxes/ghc/7.8.3//lib/ghc-7.8.3/include/ghcautoconf.h  at line 383 col
 1:  AC_APPLE_UNIVERSAL_BUILD

src/full/Agda/Syntax/Parser/Lexer.x:0:2:
    lexical error at character '\n'
*** Deleting temp files:

One thing I don't understand here is that the call mentions Lexer.hs, but the error mentions 
Lexer.x.

Janek