build: propagate $SHELL to makeinfo-wrapper.sh

A user that had an environment with SHELL=/usr/bin/fish
reported the following when trying to build info docs:

  build-aux/missing (line 4): Unsupported use of '='. In fish

* doc/local.mk: Propagate make's SHELL to our
makeinfo wrapper, so that the substituted ${SHELL}
uses a compatible shell from the Makefile.

diff --git a/doc/local.mk b/doc/local.mk
index 129def7cdb474a634b7d2cc50501910aadb66369..313a7648a1689fc530de3044bd8fc42812b9e243 100644 (file)
--- a/doc/local.mk
+++ b/doc/local.mk
@@ -25,7 +25,7 @@ doc_coreutils_TEXINFOS = \
   doc/fdl.texi \
   doc/sort-version.texi
 
-MAKEINFO = $(abs_top_builddir)/build-aux/makeinfo-wrapper.sh
+MAKEINFO = SHELL='$(SHELL)' $(abs_top_builddir)/build-aux/makeinfo-wrapper.sh
 
 # The customization variable CHECK_NORMAL_MENU_STRUCTURE is necessary with
 # makeinfo versions ≥ 6.8.