Fix two OpenAL related compiler errors

CMakeLists.txt

@@ -245,6 +245,7 @@ check_include_file(sys/time.h HAVE_SYS_TIME_H)
 check_include_file(sys/timeb.h HAVE_SYS_TIMEB_H)
 check_include_file(unistd.h HAVE_UNISTD_H)
 check_include_file(windows.h HAVE_WINDOWS_H)
+check_include_file(AL/alext.h HAVE_AL_EXT_H)
 
 if(HAVE_INTTYPES_H)
   # ShivaVG needs inttypes.h

simgear/simgear_config_cmake.h.in

@@ -13,6 +13,8 @@
 #cmakedefine HAVE_STD_ISNAN
 #cmakedefine HAVE_WINDOWS_H
 #cmakedefine HAVE_MKDTEMP
+#cmakedefine HAVE_AL_EXT_H
+
 
 #cmakedefine GCC_ATOMIC_BUILTINS_FOUND
 

simgear/sound/soundmgr_openal.cxx

@@ -762,7 +762,7 @@ bool SGSoundMgr::load( const std::string &samplepath,
     if ( !is_working() )
         return false;
 
-    ALenum format;
+    unsigned int format;
     ALsizei size;
     ALsizei freq;
     ALvoid *data;

simgear/sound/soundmgr_openal_private.hxx

@@ -29,6 +29,10 @@
 #ifndef _SG_SOUNDMGR_OPENAL_PRIVATE_HXX
 #define _SG_SOUNDMGR_OPENAL_PRIVATE_HXX 1
 
+#ifdef HAVE_CONFIG_H
+#  include <simgear_config.h>
+#endif
+
 #include <string>
 #include <vector>
 #include <map>
@@ -36,15 +40,15 @@
 #if defined(__APPLE__)
 # include <OpenAL/al.h>
 # include <OpenAL/alc.h>
-# include <OpenAL/alext.h>
 #elif defined(OPENALSDK)
 # include <al.h>
 # include <alc.h>
-# include <alext.h>
 #else
 # include <AL/al.h>
 # include <AL/alc.h>
-# include <AL/alext.h>
+# ifdef HAVE_AL_EXT_H
+#  include <AL/alext.h>
+# endif
 #endif
 
 #include <simgear/structure/SGSharedPtr.hxx>