Fix header path for audio engine on Mac.

There's a different prefix here.

Change-Id: Ifda82e19824801b1d903ab6ad40c97428fff236c
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>

config.tests/openal/main.cpp

@@ -39,7 +39,11 @@
 **
 ****************************************************************************/
 
+#if defined(HEADER_OPENAL_PREFIX)
+#include <OpenAL/al.h>
+#else
 #include <AL/al.h>
+#endif
 
 int main(int argc, char** argv)
 {

config.tests/openal/openal.pro

@@ -1,7 +1,6 @@
 SOURCES += main.cpp
 
-win32 {
-    LIBS += -lOpenAL32
-}else {
-    LIBS += -lopenal
-}
+win32: LIBS += -lOpenAL32
+unix:!mac: LIBS += -lopenal
+mac: LIBS += -framework OpenAL
+mac: DEFINES += HEADER_OPENAL_PREFIX