sundry questions

[Anthony Shipman]

1. .pc file format precision.

The man page says
  Requires: This is a comma-separated list of packages ... 
but I've noticed that most .pc files don't use commas as
separators. 

The man page does not say whether white space is allowed
around the "=" in variable declarations but there are some
.pc files which have white space e.g. icu-i18n.pc

The version checks are written as "foo >= 1.2" in the
documentation and in all .pc files. Is the white space
required around the ">="?

Is there a more precise specification of the format?

2. There is an option
       --dont-define-prefix
              This option is available only on Windows. It prevents
pkg-config from automatically trying to override the value of the
variable "prefix" in each .pc file.

When is "prefix" otherwise overridden? Does it happen only on Windows?


3. What does the following mean?

       PKG_CONFIG_TOP_BUILD_DIR
          A value to set for the magic variable pc_top_builddir which
may appear in .pc files. If the  environment  variable  is  not  set,
the default  value  '$(top_builddir)'  will be used.

I can't find any explanation of what '$(top_builddir)' refers to.


4. How is the foo-uninstalled feature used?  Is it used much?

Thanks