diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index 565799c611f365ac0c8358666d156d7fa01734cc..8a0864f26add194c380c0dc978f81e2f5d943029 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -788,14 +788,17 @@ (define bash-mesboot0
              (substitute* "config.h"
                (("#define GETCWD_BROKEN 1") "#undef GETCWD_BROKEN"))
              (let ((config.h (open-file "config.h" "a")))
-               (display (string-append "
+               (display (string-append
+                         ;; XXX TODO: remove nested ,(string-append ...) and
+                         ;; store file name on next rebuild cycle
+                         ,(string-append "
 // tcc: error: undefined symbol 'enable_hostname_completion'
 #define enable_hostname_completion(on_or_off) 0
 
-// /gnu/store/cq0cmv35s9dhilx14zaghlc08gpc0hwr-tcc-boot0-0.9.26-6.c004e9a/lib/libc.a: error: 'sigprocmask' defined twice
+// /gnu/store/" "cq0cmv35s9dhilx14zaghlc08gpc0hwr-tcc-boot0-0.9.26-6.c004e9a/lib/libc.a: error: 'sigprocmask' defined twice
 #define HAVE_POSIX_SIGNALS 1
 #define endpwent(x) 0
-")
+"))
                         config.h)
                (close config.h))
              #t))