Check the location of alsa-driver header files in configure (for doxygen)

doc/doxygen.cfg.in

@@ -0,0 +1,35 @@
+PROJECT_NAME     = "ALSA project - the C library reference"
+OUTPUT_DIRECTORY = doxygen
+GENERATE_LATEX   = NO
+GENERATE_MAN     = NO
+GENERATE_RTF	 = NO
+
+CASE_SENSE_NAMES = NO
+INPUT            = @ASOUND_PATH@/asound.h ../include/asoundlib.h ../src
+EXCLUDE		 = ../src/control/control_local.h \
+		   ../src/pcm/atomic.h \
+		   ../src/pcm/interval.h \
+		   ../src/pcm/interval_inline.h \
+		   ../src/pcm/mask.h \
+		   ../src/pcm/mask_inline.h \
+		   ../src/pcm/pcm_local.h \
+		   ../src/pcm/pcm_meter.h \
+		   ../src/pcm/pcm_plugin.h \
+		   ../src/pcm/plugin_ops.h \
+		   ../src/mixer/mixer_local.h \
+		   ../src/rawmidi/rawmidi_local.h \
+		   ../src/seq/seq_local.h
+RECURSIVE	 = YES
+FILE_PATTERNS    = *.c *.h
+#EXAMPLE_PATH     = example_test.cpp
+QUIET            = YES
+
+EXTRACT_ALL	 = NO
+EXTRACT_STATIC	 = NO
+SHOW_INCLUDE_FILES = NO
+JAVADOC_AUTOBRIEF = NO
+INHERIT_DOCS	 = YES
+ENABLED_SECTIONS = ""
+PREDEFINED	 = "DOC_HIDDEN"
+
+OPTIMIZE_OUTPUT_FOR_C = YES	# doxygen 1.2.6 option