Avoid unreproducible rbconfig.rb (always use bash to build)

Author: zeha

debian/changelog

@@ -1,6 +1,7 @@
 ruby2.3 (2.3.1-3) UNRELEASED; urgency=medium
 
   * Replace libruby2.3-dbg with automatic dbgsym packages.
+  * Avoid unreproducible rbconfig.rb (always use bash to build).
 
  -- Christian Hofstaedtler <[email protected]>  Mon, 06 Jun 2016 12:39:40 +0000
 

debian/rules

@@ -37,6 +37,9 @@ configure_options += --with-dbm-type=gdbm_compat
 export DEB_BUILD_MAINT_OPTIONS = hardening=+bindnow
 configure_options += $(shell dpkg-buildflags --export=configure)
 
+# Always build with /bin/bash, to get consistent rbconfig.rb (which embeds SHELL).
+export SHELL := /bin/bash
+
 vtcltk=8.6
 configure_options += --with-tcltkversion=$(vtcltk)
 configure_options += --with-tclConfig-dir=/usr/lib/$(DEB_HOST_MULTIARCH)/tcl$(vtcltk)/tclConfig.sh