I'm trying to build gnucash 5.15. It works fine on f43 and f44, but I get the following on rawhide.

In /usr/bin/guild3.0:
    72:17 19 (main _)
In srfi/srfi-1.scm:
    750:9 18 (for-each #<procedure 7fd173245230 at scripts/compile.scm:276:14 (file)> ("/builddir/build/BUILD/gnucash-5.15-build/gnucash-5.15/common/test-core/unittest-support.scm"))
In scripts/compile.scm:
   279:27 17 (_ _)
In system/base/target.scm:
     82:6 16 (with-target _ _)
In system/base/compile.scm:
    187:6 15 (compile-file "/builddir/build/BUILD/gnucash-5.15-build/gnucash-5.15/common/test-core/unittest-support.scm" #:output-file _ #:from _ #:to _ #:env _ #:optimization-level _ #:warning-level _ #:opts _ #:canonicalization _)
     53:4 14 (call-with-output-file/atomic _ _ _)
In ice-9/boot-9.scm:
  1784:12 13 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
In system/base/compile.scm:
    69:11 12 (_)
   190:11 11 (_ #<closed: file 7fd16e06d2a0>)
   331:39 10 (read-and-compile #<input: unittest-support.scm 11> #:from _ #:to _ #:env _ #:optimization-level _ #:warning-level _ #:opts _)
   261:27  9 (_ _ _)
In ice-9/boot-9.scm:
   2890:4  8 (save-module-excursion #<procedure 7fd16e0722e0 at language/scheme/compile-tree-il.scm:29:3 ()>)
In language/scheme/compile-tree-il.scm:
    31:16  7 (_)
In ice-9/psyntax.scm:
  1111:30  6 (expand-top-sequence (#<syntax:unittest-support.scm:21:0 (#<syntax:unittest-support.scm:21:1 eval-when> #<syntax:unittest-support.scm:22:6 (#<syntax:unittest-support.scm:22:7 compile> #<syntax:unittest-support.scm:22:15 load> #<syntax:unittest-support.scm:22:20 eval> #<syntax:unittest-support.scm:22:25 expand>)> #<syntax:unittest-support.scm:23:6 (#<syntax:unittest-support.scm:23:7 load-extension> #<syntax:unittest-support.scm:23:22 "libtest-core-guile"> #<syntax:unittest-supp…>) …)
  1104:15  5 (lp _)
    182:4  4 (lp _)
In unknown file:
           3 (load-extension "libtest-core-guile" "scm_init_unittest_support_module")
In system/foreign-library.scm:
    294:4  2 (load-foreign-library _ #:extensions _ #:search-ltdl-library-path? _ #:search-path _ #:search-system-paths? _ #:lazy? _ #:global? _ #:host-type-rename? _ #:allow-dll-version-suffix? _)
In unknown file:
           1 (dlopen "libtest-core-guile.so" 1)
In ice-9/boot-9.scm:
  1705:22  0 (raise-exception _ #:continuable? _)
ice-9/boot-9.scm:1705:22: In procedure raise-exception:
In procedure dlopen: file "libtest-core-guile.so", message "/builddir/build/BUILD/gnucash-5.15-build/gnucash-5.15/redhat-linux-build/lib64/libgnc-core-utils.so: undefined symbol: _ZN5boost10filesystem16filesystem_errorD1Ev"