apidoc: Limit INPUT to src subdirectory and README.md

While 0909bf6c explicitly includes the whole source tree (to cover README.md),
this has the unpleasant side effect of covering a workspace under "testing"
with all its sources, or any other potential subdirectory that exists.

Doxyfile.in

@@ -743,7 +743,7 @@ WARN_LOGFILE           =
 # spaces.
 # Note: If this tag is empty the current directory is searched.
 
-INPUT                  = @SRC_DIR@/
+INPUT                  = @SRC_DIR@/src @SRC_DIR@/README.md
 
 # This tag can be used to specify the character encoding of the source files
 # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses

Makefile.am

@@ -34,7 +34,7 @@ Doxyfile :	Doxyfile.in
 		sed \
 		-e "s:\@PACKAGE_VERSION\@:$(PACKAGE_VERSION):" \
 		-e "s:\@PACKAGE_NAME\@:$(PACKAGE_NAME):" \
-		-e "s:\@SRC_DIR\@:$(srcdir):" \
+		-e "s:\@SRC_DIR\@:$(srcdir):g" \
 		$(srcdir)/$@.in > $@
 
 apidoc :	Doxyfile