Fix a number of things with the generated docs, including translating triple-backtick code blocks into a form doxygen understands.

doc/Doxyfile.in

@@ -805,7 +805,13 @@ EXCLUDE_SYMLINKS       = NO
 # Note that the wildcards are matched against the file with absolute path, so to
 # exclude all test directories for example use the pattern */test/*
 
-EXCLUDE_PATTERNS       =
+EXCLUDE_PATTERNS       = \
+	*/json_object_private.h \
+	*/debug.h \
+	*/*config.h \
+	*/random_seed.h \
+	*/strerror_*h \
+	*/*compat.h
 
 # The EXCLUDE_SYMBOLS tag can be used to specify one or more symbol names
 # (namespaces, classes, functions, etc.) that should be excluded from the
@@ -816,7 +822,11 @@ EXCLUDE_PATTERNS       =
 # Note that the wildcards are matched against the file with absolute path, so to
 # exclude all test directories use the pattern */test/*
 
-EXCLUDE_SYMBOLS        =
+EXCLUDE_SYMBOLS        = \
+	_json_c_* \
+	_LH_* \
+	_printbuf_* \
+	__STRING
 
 # The EXAMPLE_PATH tag can be used to specify one or more files or directories
 # that contain example code fragments that are included (see the \include
@@ -859,7 +869,7 @@ IMAGE_PATH             =
 # code is scanned, but not when the output code is generated. If lines are added
 # or removed, the anchors will not be placed correctly.
 
-INPUT_FILTER           =
+INPUT_FILTER           = @CMAKE_CURRENT_SOURCE_DIR@/fixup_markdown.sh
 
 # The FILTER_PATTERNS tag can be used to specify filters on a per file pattern
 # basis. Doxygen will compare the file name with each pattern and apply the

doc/fixup_markdown.sh

@@ -0,0 +1,6 @@
+#!/bin/sh
+#
+# Doxygen markdown doesn't support triple-backticks like github does.
+# Convert all of those to space-prefixed blocks instead.
+#
+awk '/```/ { prefix=!prefix; print ""; next; } { if (prefix) { printf "    "; } print $0; } ' "$@"