Add scripts/apidoc_full.sh

This re-introduces the apidoc with full config.h, but hopefully with the race
conditions and other issues that the previous implementation had.

Adapt doxygen test script to use that new script, and also check for errors
in addition to warnings while at it.

tests/scripts/doxygen.sh

@@ -10,7 +10,7 @@ if [ -d library -a -d include -a -d tests ]; then :; else
     exit 1
 fi
 
-if make apidoc > doc.out 2>doc.err; then :; else
+if scripts/apidoc_full.sh > doc.out 2>doc.err; then :; else
     cat doc.err
     echo "FAIL" >&2
     exit 1;
@@ -20,7 +20,7 @@ cat doc.out doc.err | \
     grep -v "warning: ignoring unsupported tag" \
     > doc.filtered
 
-if grep "warning" doc.filtered; then
+if egrep "(warning|error):" doc.filtered; then
     echo "FAIL" >&2
     exit 1;
 fi