consistent API checks

consistent ordering of AC_MSG, additional library checks and var-setting.
also, use "=" rather than "=" when testing for equality

configure.ac

@@ -127,50 +127,56 @@ AC_CANONICAL_HOST
 AC_MSG_CHECKING(for audio API)
 
 AC_ARG_WITH(jack, [  --with-jack = choose JACK server support (mac and linux only)])
-AS_IF([test "x$with_jack" == "xyes"], [
-  api="$api -D__UNIX_JACK__"
+AS_IF([test "x$with_jack" = "xyes"], [
   AC_MSG_RESULT(using JACK)
-  AC_CHECK_LIB(jack, jack_client_open, , AC_MSG_ERROR(JACK support requires the jack library!))])
+  AC_CHECK_LIB(jack, jack_client_open, , AC_MSG_ERROR(JACK support requires the jack library!))
+  api="$api -D__UNIX_JACK__"
+])
 
 case $host in
   *-*-netbsd*)
-  AS_IF([test "$api" == ""], [
+  AS_IF([test "x$api" = "x"], [
     AC_MSG_RESULT(using OSS)
     api="$api -D__LINUX_OSS__"
-    LIBS="$LIBS -lossaudio"
-    AC_CHECK_LIB(pthread, pthread_create, , AC_MSG_ERROR(RtAudio requires the pthread library!))])
+    AC_CHECK_LIB(ossaudio, main, , AC_MSG_ERROR([RtAudio requires the ossaudio library]))
+    AC_CHECK_LIB(pthread, pthread_create, , AC_MSG_ERROR(RtAudio requires the pthread library!))
+  ])
   ;;
 
   *-*-freebsd*)
-  AS_IF([test "$api" == ""], [
+  AS_IF([test "x$api" = "x"], [
     AC_MSG_RESULT(using OSS)
     api="$api -D__LINUX_OSS__"
-    LIBS="$LIBS -lossaudio"
-    AC_CHECK_LIB(pthread, pthread_create, , AC_MSG_ERROR(RtAudio requires the pthread library!))])
+    AC_CHECK_LIB(ossaudio, main, , AC_MSG_ERROR([RtAudio requires the ossaudio library]))
+    AC_CHECK_LIB(pthread, pthread_create, , AC_MSG_ERROR(RtAudio requires the pthread library!))
+  ])
   ;;
 
   *-*-linux*)
   # Look for ALSA flag
   AC_ARG_WITH(alsa, [  --with-alsa = choose native ALSA API support (linux only)])
-  AS_IF([test "x$with_alsa" == "xyes"], [
+  AS_IF([test "x$with_alsa" = "xyes"], [
+    AC_MSG_RESULT(using ALSA)
     api="$api -D__LINUX_ALSA__"
     req="$req alsa"
-    AC_MSG_RESULT(using ALSA)
-    AC_CHECK_LIB(asound, snd_pcm_open, , AC_MSG_ERROR(ALSA support requires the asound library!))])
+    AC_CHECK_LIB(asound, snd_pcm_open, , AC_MSG_ERROR(ALSA support requires the asound library!))
+  ])
 
   # Look for PULSE flag
   AC_ARG_WITH(pulse, [  --with-pulse = choose PulseAudio API support (linux only)])
-  AS_IF([test "x$with_pulse" == "xyes"], [
+  AS_IF([test "x$with_pulse" = "xyes"], [
+    AC_MSG_RESULT(using PulseAudio)
     api="$api -D__LINUX_PULSE__"
     req="$req libpulse-simple"
-    AC_MSG_RESULT(using PulseAudio)
-    AC_CHECK_LIB(pulse-simple, pa_simple_flush, , AC_MSG_ERROR(PulseAudio support requires the pulse-simple library!))])
+    AC_CHECK_LIB(pulse-simple, pa_simple_flush, , AC_MSG_ERROR(PulseAudio support requires the pulse-simple library!))
+  ])
 
   # Look for OSS flag
   AC_ARG_WITH(oss, [  --with-oss = choose OSS API support (unixes)])
-  AS_IF([test "x$with_oss" == "xyes"], [
+  AS_IF([test "x$with_oss" = "xyes"], [
+    AC_MSG_RESULT(using OSS)
     api="$api -D__LINUX_OSS__"
-    AC_MSG_RESULT(using OSS)])
+  ])
 
   # If no audio api flags specified, use ALSA
   AS_IF([test "x$api" = "x" ], [
@@ -185,11 +191,12 @@ case $host in
   *-apple*)
   # Look for Core flag
   AC_ARG_WITH(core, [  --with-core = choose CoreAudio API support (mac only)])
-  AS_IF([test "x$with_core" == "xyes"], [
-    api="$api -D__MACOSX_CORE__"
+  AS_IF([test "x$with_core" = "xyes"], [
     AC_MSG_RESULT(using CoreAudio)
+    api="$api -D__MACOSX_CORE__"
     AC_CHECK_HEADER(CoreAudio/CoreAudio.h, [], [AC_MSG_ERROR(CoreAudio header files not found!)] )
-    LIBS="$LIBS -framework CoreAudio -framework CoreFoundation" ])
+    LIBS="$LIBS -framework CoreAudio -framework CoreFoundation"
+  ])
 
   # If no audio api flags specified, use CoreAudio
   AS_IF([test "x$api" = "x" ], [
@@ -206,24 +213,27 @@ case $host in
 
   *-mingw32*)
   AC_ARG_WITH(asio, [  --with-asio = choose ASIO API support (windoze only)])
-  AS_IF([test "x$with_asio" == "xyes"], [
-    api="$api -D__WINDOWS_ASIO__"
+  AS_IF([test "x$with_asio" = "xyes" ], [
     AC_MSG_RESULT(using ASIO)
-    AC_SUBST( objects, ["asio.o asiodrivers.o asiolist.o iasiothiscallresolver.o"] ) ])
+    api="$api -D__WINDOWS_ASIO__"
+    AC_SUBST( objects, ["asio.o asiodrivers.o asiolist.o iasiothiscallresolver.o"] )
+  ])
 
   # Look for DirectSound flag
   AC_ARG_WITH(ds, [  --with-ds = choose DirectSound API support (windoze only)])
-  AS_IF([test "x$with_ds" == "xyes"], [
-    api="$api -D__WINDOWS_DS__"
+  AS_IF([test "x$with_ds" = "xyes" ], [
     AC_MSG_RESULT(using DirectSound)
-    LIBS="-ldsound -lwinmm $LIBS" ])
+    api="$api -D__WINDOWS_DS__"
+    LIBS="-ldsound -lwinmm $LIBS"
+  ])
 
   # Look for WASAPI flag
   AC_ARG_WITH(wasapi, [  --with-wasapi = choose Windows Audio Session API support (windoze only)])
-  AS_IF([test "x$with_wasapi" == "xyes"], [
-    api="$api -D__WINDOWS_WASAPI__"
+  AS_IF([test "x$with_wasapi" = "xyes"], [
     AC_MSG_RESULT(using WASAPI)
-    LIBS="-lwinmm -luuid -lksuser $LIBS" ])
+    api="$api -D__WINDOWS_WASAPI__"
+    LIBS="-lwinmm -luuid -lksuser $LIBS"
+  ])
 
   # If no audio api flags specified, use DS
   AS_IF([test "x$api" = "x" ], [