mes: Add string-null?.
-rw-r--r-- 533 .gitignore
-rw-r--r-- 888 AUTHORS
-rw-r--r-- 3563 BOOTSTRAP
-rw-r--r-- 35147 COPYING
-rw-r--r-- 354 GNUmakefile
-rw-r--r-- 10682 HACKING
-rw-r--r-- 1421 INSTALL
-rw-r--r-- 13627 NEWS
-rw-r--r-- 2679 README
drwxr-xr-x - build-aux
-rwxr-xr-x 2096 build.sh
-rwxr-xr-x 1562 check-mescc.sh
-rwxr-xr-x 1637 check.sh
-rwxr-xr-x 10041 configure
drwxr-xr-x - doc
drwxr-xr-x - guile
-rw-r--r-- 7601 guix.scm
drwxr-xr-x - include
-rwxr-xr-x 739 install.sh
drwxr-xr-x - lib
-rwxr-xr-x 27370 make.scm
drwxr-xr-x - module
drwxr-xr-x - scaffold
drwxr-xr-x - scripts
drwxr-xr-x - src
drwxr-xr-x - stage0
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drwxr-xr-x - tests