Add the 'guild' and 'guile' variables to 'guile-2.0.pc'.

* configure.ac: Remove meta/guile-2.0.pc and
  meta/guile-2.0-uninstalled.pc from 'AC_CONFIG_FILES'.
* meta/Makefile.am (substitute): New variable.
  (guile-2.0.pc, guile-2.0-uninstalled.pc): New targets.
  (guile-config, guild): Use $(substitute) instead of duplicated sed
  script.
  (CLEANFILES): Add the .pc files.
* meta/guile-2.0.pc.in (bindir, guild, guile): New variables.
* doc/ref/libguile-parallel.texi (Parallel Installations): Document the
  'guild' and 'guile' pkg-config variables.

meta/Makefile.am

@@ -44,24 +44,47 @@ pkgconfig_DATA = guile-2.0.pc
 aclocaldir = $(datadir)/aclocal
 aclocal_DATA = guile.m4
 
+# Script to instantiate substitution variables found on the standard
+# input.  We do this from the Makefile because we need things like
+# $(program_transform_name), which are not usable from 'configure.ac'.
+substitute =								\
+  guile="`echo guile | $(SED) -e '$(program_transform_name)'`" ;	\
+  guild="`echo guild | $(SED) -e '$(program_transform_name)'`" ;	\
+  installed_guile="@bindir@/$$guile" ;					\
+  $(SED) -e "s,[@]PACKAGE_NAME[@],$(PACKAGE_NAME),g"			\
+	 -e "s,[@]PACKAGE_BUGREPORT[@],$(PACKAGE_BUGREPORT),g"		\
+	 -e "s,[@]PKG_CONFIG[@],$(PKG_CONFIG),g"			\
+	 -e "s,[@]pkgconfigdir[@],$(pkgconfigdir),g"			\
+	 -e "s,[@]prefix[@],$(prefix),g"				\
+	 -e "s,[@]exec_prefix[@],$(exec_prefix),g"			\
+	 -e "s,[@]bindir[@],$(bindir),g"				\
+	 -e "s,[@]libdir[@],$(libdir),g"				\
+	 -e "s,[@]includedir[@],$(includedir),g"			\
+	 -e "s,[@]datarootdir[@],$(datarootdir),g"			\
+	 -e "s,[@]datadir[@],$(datadir),g"				\
+	 -e "s,[@]sitedir[@],$(sitedir),g"				\
+	 -e "s,[@]guile[@],$$guile,g"					\
+	 -e "s,[@]guild[@],$$guild,g"					\
+	 -e "s,[@]installed_guile[@],$$installed_guile,g"
+
+guile-2.0.pc: guile-2.0.pc.in
+	$(substitute) < "$<" > "$@.out"
+	mv "$@.out" "$@"
+
+guile-2.0-uninstalled.pc: guile-2.0-uninstalled.pc.in
+	$(substitute) < "$<" > "$@.out"
+	mv "$@.out" "$@"
+
 guile-config: $(srcdir)/guile-config.in $(top_builddir)/config.status
-	guile="@bindir@/`echo guile | $(SED) -e '$(program_transform_name)'`" ;	\
-	$(SED) -e "s,[@]pkgconfigdir[@],$(pkgconfigdir),g"			\
-	       -e "s,[@]PKG_CONFIG[@],$(PKG_CONFIG),g"				\
-	       -e "s,[@]installed_guile[@],$$guile,g"				\
-	  < "$(srcdir)/guile-config.in"						\
-	  > "$@.out"
+	$(substitute) < "$<" > "$@.out"
 	chmod +x "$@.out"
 	mv "$@.out" "$@"
 
 guild: $(srcdir)/guild.in $(top_builddir)/config.status
-	guile="@bindir@/`echo guile | $(SED) -e '$(program_transform_name)'`" ;	\
-	$(SED) -e "s,[@]installed_guile[@],$$guile,g"				\
-	       -e "s,[@]PACKAGE_NAME[@],$(PACKAGE_NAME),g"			\
-	       -e "s,[@]PACKAGE_BUGREPORT[@],$(PACKAGE_BUGREPORT),g"		\
-	  < "$(srcdir)/guild.in"						\
-	  > "$@.out"
+	$(substitute) < "$<" > "$@.out"
 	chmod +x "$@.out"
 	mv "$@.out" "$@"
 
-CLEANFILES = guile-config guild
+CLEANFILES =					\
+  guile-config guild				\
+  guile-2.0.pc guile-2.0-uninstalled.pc

meta/guile-2.0.pc.in

@@ -1,5 +1,6 @@
 prefix=@prefix@
 exec_prefix=@exec_prefix@
+bindir=@bindir@
 libdir=@libdir@
 includedir=@includedir@
 datarootdir=@datarootdir@
@@ -11,6 +12,12 @@ sitedir=@sitedir@
 extensiondir=@libdir@/guile/@GUILE_EFFECTIVE_VERSION@/extensions
 libguileinterface=@LIBGUILE_INTERFACE@
 
+# Actual name of the 'guile' and 'guild' programs.  This is
+# particularly useful when '--program-transform-name' or similar has
+# been used.
+guild=${bindir}/@guild@
+guile=${bindir}/@guile@
+
 Name: GNU Guile
 Description: GNU's Ubiquitous Intelligent Language for Extension
 Version: @GUILE_VERSION@