Allow $GUILE_FOR_BUILD to use its own environment when cross-compiling.

* am/guilec (.scm.go): Use `-L' to specify the search path.
* module/Makefile.am (ice-9/psyntax-pp.go): Likewise.

* meta/uninstalled-env.in (top_builddir): Leave $GUILE_LOAD_PATH,
  $GUILE_SYSTEM_PATH, and $GUILE_SYSTEM_EXTENSIONS_PATH unchanged when
  cross-compiling.

am/guilec

@@ -28,4 +28,7 @@ SUFFIXES = .scm .go
 .scm.go:
 	$(AM_V_GUILEC)GUILE_AUTO_COMPILE=0			\
 	$(top_builddir)/meta/uninstalled-env			\
-	guild compile --target="$(host)" $(GUILE_WARNINGS) -o "$@" "$<"
+	guild compile --target="$(host)" $(GUILE_WARNINGS)	\
+	  -L "$(abs_srcdir)" -L "$(abs_builddir)"		\
+	  -L "$(abs_top_srcdir)/guile-readline"			\
+	  -o "$@" "$<"

meta/uninstalled-env.in

@@ -46,6 +46,15 @@ top_builddir="@top_builddir_absolute@"
     exit 1
 }
 
+# When cross-compiling, let $GUILE_FOR_BUILD use its own .go files since
+# the ones that are being built may be incompatible ($GUILE_FOR_BUILD is
+# typically used to run `guild compile --target=$host'.)  Likewise,
+# $GUILE_FOR_BUILD must use its own source files when booting; for
+# instance, $srcdir/module/ice-9/boot-9.scm must not be in its search
+# path, because it would then end up using its C evaluator to run the
+# compiler.
+if test "@cross_compiling@" = "no"
+then
     if [ x"$GUILE_LOAD_PATH" = x ]
     then
 	GUILE_LOAD_PATH="${top_srcdir}/module:${top_srcdir}/guile-readline:${top_srcdir}"
@@ -71,10 +80,6 @@ else
     fi
     export GUILE_LOAD_PATH
 
-# When cross-compiling, let $GUILE_FOR_BUILD use its own .go files since
-# the ones that are being built may be incompatible.
-if test "@cross_compiling@" = "no"
-then
     if test "x$GUILE_LOAD_COMPILED_PATH" = "x"
     then
 	GUILE_LOAD_COMPILED_PATH="${top_builddir}/module:${top_builddir}/guile-readline:${top_builddir}"
@@ -91,7 +96,6 @@ then
 	done
     fi
     export GUILE_LOAD_COMPILED_PATH
-fi
 
     # Don't look in installed dirs for guile modules
     if ( env | grep -v '^GUILE_SYSTEM_PATH=' > /dev/null ); then
@@ -108,6 +112,7 @@ if ( env | grep -v '^GUILE_SYSTEM_EXTENSIONS_PATH=' > /dev/null ); then
 	GUILE_SYSTEM_EXTENSIONS_PATH=
 	export GUILE_SYSTEM_EXTENSIONS_PATH
     fi
+fi
 
 # handle LTDL_LIBRARY_PATH (no clobber)
 for dir in $subdirs_with_ltlibs ; do

module/Makefile.am

@@ -79,10 +79,13 @@ ice-9/psyntax-pp.scm.gen:
 
 .PHONY: ice-9/psyntax-pp.scm.gen
 
+# Keep this rule in sync with that in `am/guilec'.
 ice-9/psyntax-pp.go: ice-9/psyntax.scm ice-9/psyntax-pp.scm
 	$(AM_V_GUILEC)GUILE_AUTO_COMPILE=0				\
 	$(top_builddir)/meta/uninstalled-env				\
 	guild compile --target="$(host)" $(GUILE_WARNINGS)		\
+	  -L "$(abs_srcdir)" -L "$(abs_builddir)"			\
+	  -L "$(abs_top_srcdir)/guile-readline"				\
 	  -o "ice-9/psyntax-pp.go" "$(srcdir)/ice-9/psyntax.scm"
 
 SCHEME_LANG_SOURCES =						\