Only declare backend options when the backend is available

1 files changed, 20 insertions, 22 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 68a58cae..0d868c9e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,14 +37,6 @@ ELSE()
 ENDIF()
 
 
-OPTION(ALSOFT_BACKEND_MMDEVAPI "Check for MMDevApi backend"           ON)
-OPTION(ALSOFT_BACKEND_WINMM    "Check for Windows Multimedia backend" ON)
-OPTION(ALSOFT_BACKEND_OPENSL   "Check for OpenSL backend"             ON)
-
-OPTION(ALSOFT_REQUIRE_MMDEVAPI "Require MMDevApi"                   OFF)
-OPTION(ALSOFT_REQUIRE_WINMM    "Require Windows Multimedia backend" OFF)
-OPTION(ALSOFT_REQUIRE_OPENSL   "Require OpenSL backend"             OFF)
-
 OPTION(ALSOFT_DLOPEN  "Check for the dlopen API for loading optional libs"  ON)
 
 OPTION(ALSOFT_WERROR  "Treat compile warnings as errors"      OFF)
@@ -738,10 +730,12 @@ IF(ALSOFT_REQUIRE_DSOUND AND NOT HAVE_DSOUND)
 ENDIF()
 
 # Check for MMDevApi backend
+OPTION(ALSOFT_REQUIRE_MMDEVAPI "Require MMDevApi backend" OFF)
 IF(HAVE_WINDOWS_H)
-    IF(ALSOFT_BACKEND_MMDEVAPI)
-        CHECK_INCLUDE_FILE(mmdeviceapi.h HAVE_MMDEVICEAPI_H)
-        IF(HAVE_MMDEVICEAPI_H)
+    CHECK_INCLUDE_FILE(mmdeviceapi.h HAVE_MMDEVICEAPI_H)
+    IF(HAVE_MMDEVICEAPI_H)
+        OPTION(ALSOFT_BACKEND_MMDEVAPI "Enable MMDevApi backend" ON)
+        IF(ALSOFT_BACKEND_MMDEVAPI)
             SET(HAVE_MMDEVAPI 1)
             SET(ALC_OBJS  ${ALC_OBJS} Alc/backends/mmdevapi.c)
 
@@ -754,12 +748,14 @@ IF(ALSOFT_REQUIRE_MMDEVAPI AND NOT HAVE_MMDEVAPI)
 ENDIF()
 
 # Check MMSystem backend
+OPTION(ALSOFT_REQUIRE_WINMM "Require Windows Multimedia backend" OFF)
 IF(HAVE_WINDOWS_H)
-    IF(ALSOFT_BACKEND_WINMM)
-        CHECK_INCLUDE_FILES("windows.h;mmsystem.h" HAVE_MMSYSTEM_H -D_WIN32_WINNT=0x0502)
-        IF(HAVE_MMSYSTEM_H)
-            CHECK_SHARED_FUNCTION_EXISTS(waveOutOpen "windows.h;mmsystem.h" winmm "" HAVE_LIBWINMM)
-            IF(HAVE_LIBWINMM)
+    CHECK_INCLUDE_FILES("windows.h;mmsystem.h" HAVE_MMSYSTEM_H -D_WIN32_WINNT=0x0502)
+    IF(HAVE_MMSYSTEM_H)
+        CHECK_SHARED_FUNCTION_EXISTS(waveOutOpen "windows.h;mmsystem.h" winmm "" HAVE_LIBWINMM)
+        IF(HAVE_LIBWINMM)
+            OPTION(ALSOFT_BACKEND_WINMM "Enable Windows Multimedia backend" ON)
+            IF(ALSOFT_BACKEND_WINMM)
                 SET(HAVE_WINMM 1)
                 SET(ALC_OBJS  ${ALC_OBJS} Alc/backends/winmm.c)
                 SET(BACKENDS  "${BACKENDS} WinMM,")
@@ -823,7 +819,7 @@ FIND_LIBRARY(COREAUDIO_FRAMEWORK
              PATHS /System/Library/Frameworks
 )
 IF(COREAUDIO_FRAMEWORK)
-    OPTION(ALSOFT_BACKEND_COREAUDIO "Check for CoreAudio backend" ON)
+    OPTION(ALSOFT_BACKEND_COREAUDIO "Enable CoreAudio backend" ON)
     IF(ALSOFT_BACKEND_COREAUDIO)
         SET(HAVE_COREAUDIO 1)
         SET(ALC_OBJS  ${ALC_OBJS} Alc/backends/coreaudio.c)
@@ -850,11 +846,13 @@ IF(ALSOFT_REQUIRE_COREAUDIO AND NOT HAVE_COREAUDIO)
 ENDIF()
 
 # Check for OpenSL (Android) backend
-IF(ALSOFT_BACKEND_OPENSL)
-    CHECK_INCLUDE_FILES("SLES/OpenSLES.h;SLES/OpenSLES_Android.h" HAVE_SLES_OPENSLES_ANDROID_H)
-    IF(HAVE_SLES_OPENSLES_ANDROID_H)
-        CHECK_SHARED_FUNCTION_EXISTS(slCreateEngine "SLES/OpenSLES.h" OpenSLES "" HAVE_LIBOPENSLES)
-        IF(HAVE_LIBOPENSLES)
+OPTION(ALSOFT_REQUIRE_OPENSL "Require OpenSL backend" OFF)
+CHECK_INCLUDE_FILES("SLES/OpenSLES.h;SLES/OpenSLES_Android.h" HAVE_SLES_OPENSLES_ANDROID_H)
+IF(HAVE_SLES_OPENSLES_ANDROID_H)
+    CHECK_SHARED_FUNCTION_EXISTS(slCreateEngine "SLES/OpenSLES.h" OpenSLES "" HAVE_LIBOPENSLES)
+    IF(HAVE_LIBOPENSLES)
+        OPTION(ALSOFT_BACKEND_OPENSL "Enable OpenSL backend" ON)
+        IF(ALSOFT_BACKEND_OPENSL)
             SET(HAVE_OPENSL 1)
             SET(ALC_OBJS  ${ALC_OBJS} Alc/backends/opensl.c)
             SET(BACKENDS  "${BACKENDS} OpenSL,")