Resolving dependencies...
Downloading projectroot-0.1.0.0...
Configuring projectroot-0.1.0.0...
Building projectroot-0.1.0.0...
Preprocessing library projectroot-0.1.0.0...
[1 of 1] Compiling System.Directory.ProjectRoot ( src/System/Directory/ProjectRoot.hs, dist/build/System/Directory/ProjectRoot.o )
projectroot/libprojectroot.c: In function ‘is_project_root’:

projectroot/libprojectroot.c:51:3:
     error: ‘for’ loop initial declarations are only allowed in C99 mode
       for(int i = 0; i < N_CANDIDATES; i++) {
       ^

projectroot/libprojectroot.c:51:3:
     note: use option -std=c99 or -std=gnu99 to compile your code
Failed to install projectroot-0.1.0.0
cabal: Error: some packages failed to install:
projectroot-0.1.0.0 failed during the building phase. The exception was:
ExitFailure 1