CMake build fails

[nurupo]

The FindOpenAL.cmake distributed with CMake says

# This makes the presumption that you are include al.h like
# #include "al.h"
# and not
# #include <AL/al.h>
# The reason for this is that the latter is not entirely portable.
# Windows/Creative Labs does not by default put their headers in AL/ and
# OS X uses the convention <OpenAL/al.h>.

Yet, the source code in this repo uses #include <AL/al.h>, which fails horribly.

In my particular case, I have installed OpenAL into $OPENAL_PREFIX. The FindOpenAL.cmake says that if you have installed OpenAL in a non-system wide manner, set $OPENALDIR to where it is installed. So I do

export OPENALDIR=$OPENAL_PREFIX
cmake -DCMAKE_INSTALL_PREFIX=$ALUT_DIR -DBUILD_EXAMPLES=OFF -DBUILD_STATIC=ON -DBUILD_TESTS=OFF .
make

and during the compilation I get

Scanning dependencies of target alut
[  5%] Building C object src/CMakeFiles/alut.dir/alutBufferData.c.o
In file included from /root/freealut/src/alutInternal.h:38:0,
                 from /root/freealut/src/alutBufferData.c:1:
/root/freealut/include/AL/alut.h:11:19: fatal error: AL/al.h: No such file or directory
 #include <AL/al.h>
                   ^
compilation terminated.
src/CMakeFiles/alut.dir/build.make:54: recipe for target 'src/CMakeFiles/alut.dir/alutBufferData.c.o' failed
make[2]: *** [src/CMakeFiles/alut.dir/alutBufferData.c.o] Error 1
CMakeFiles/Makefile2:77: recipe for target 'src/CMakeFiles/alut.dir/all' failed
make[1]: *** [src/CMakeFiles/alut.dir/all] Error 2
Makefile:117: recipe for target 'all' failed
make: *** [all] Error 2

If you call make VERBOSE=1, you see

cd /root/freealut/src && /usr/bin/cc  -DHAVE_CONFIG_H=1 -DHAVE_GCC_VISIBILITY -D__NO_CTYPE=1 -Dalut_EXPORTS -finline-functions -ffast-math -fomit-frame-pointer -fvisibility=hidden -fPIC -fPIC -I/root/freealut/include -I/root/prefix_openal/include/AL -I/root/freealut    -o CMakeFiles/alut.dir/alutBufferData.c.o   -c /root/freealut/src/alutBufferData.c
In file included from /root/freealut/src/alutInternal.h:38:0,
                 from /root/freealut/src/alutBufferData.c:1:
/root/freealut/include/AL/alut.h:11:19: fatal error: AL/al.h: No such file or directory
 #include <AL/al.h>
                   ^
compilation terminated.

Note that it does -I/root/prefix_openal/include/AL. It does so because that's what CMake's FindOpenAL.cmake sets the OPENAL_INCLUDE_DIR to, while the source code expects CMake to set OPENAL_INCLUDE_DIR to /root/prefix_openal/include.

tl;dr: the source code, at least when using the CMake build system, should be using #include "al.h" instead #include <AL/al.h>.