Added option to control dynamic loading of OpenAL

Dynamic loading is enabled by default, set DYN_OPENAL to OFF to link with static or dynamic library

# Conflicts:
#	src/sound/oalsound.cpp
#	src/sound/oalsound.h

src/CMakeLists.txt

@@ -28,6 +28,7 @@ if( ZD_CMAKE_COMPILER_IS_GNUCXX_COMPATIBLE )
 endif()
 
 option( DYN_FLUIDSYNTH "Dynamically load fluidsynth" ON )
+option( DYN_OPENAL "Dynamically load OpenAL" ON )
 
 if( APPLE )
     option( OSX_COCOA_BACKEND "Use native Cocoa backend instead of SDL" ON )
@@ -230,6 +231,16 @@ if( NOT NO_OPENAL )
 	mark_as_advanced(CLEAR OPENAL_INCLUDE_DIR)
 	if( OPENAL_INCLUDE_DIR )
 		include_directories( ${OPENAL_INCLUDE_DIR} )
+		if( DYN_OPENAL )
+			add_definitions( -DDYN_OPENAL )
+		else()
+			mark_as_advanced(CLEAR OPENAL_LIBRARY)
+			if( OPENAL_LIBRARY )
+				set( ZDOOM_LIBS ${OPENAL_LIBRARY} ${ZDOOM_LIBS} )
+			else()
+				set( NO_OPENAL ON )
+			endif()
+		endif()
 	else()
 		set( NO_OPENAL ON )
 	endif()

src/sound/oalload.h

@@ -1,7 +1,7 @@
 #ifndef OALDEF_H
 #define OALDEF_H
 
-#ifndef NO_OPENAL
+#if !defined NO_OPENAL && defined DYN_OPENAL
 
 #ifndef _WIN32
 typedef void* FARPROC;

src/sound/oalsound.cpp

@@ -83,6 +83,8 @@ bool IsOpenALPresent()
 {
 #ifdef NO_OPENAL
 	return false;
+#elif !defined DYN_OPENAL
+	return true;
 #else
 	static bool cached_result = false;
 	static bool done = false;

src/sound/oalsound.h

@@ -12,7 +12,9 @@
 
 #ifndef NO_OPENAL
 
+#ifdef DYN_OPENAL
 #define AL_NO_PROTOTYPES
+#endif // DYN_OPENAL
 
 #include "al.h"
 #include "alc.h"