The build system ingores comments

Previously a line like

%require("histogram");

was in a file of the isisscripts, but ended up as

try {require("histogram");} catch AnyError: {;};

in isisscripts.sl. The effect was noticed because the line, which was commented out, was removed in 8ef25936 which caused all the histogram routines to not be loaded by default. Whether this on its own is a good thing or not is open for debate, because the isisscripts themselves do not depend on histogram.sl. However, the fact that the build system did not recognize the original line as a comment might be unwanted behavior.