[AC21.5] Report full compiler command

APPROVE COMMIT 21.5

This patch reports the full compiler command in Installation.

It really ought to break out the different categories of switches
(warnings, include path, library path, linked libraries etc), but
I've had this sitting in mq for ages, and I've just decided I'm not
going to get to it.  This is better than nothing.

Changes to configure omitted.

diff -r 32f4ae21abc5 ChangeLog
--- a/ChangeLog	Tue May 05 12:45:20 2015 +0900
+++ b/ChangeLog	Tue May 05 13:04:26 2015 +0900
@@ -1,3 +1,8 @@
+2015-05-05  Stephen J. Turnbull  <[email protected]>
+
+	* configure.ac (Installation): Report all compiler switches.
+	* configure: Regenerate.
+
 2015-05-05  Stephen J. Turnbull  <[email protected]>
 
 	* configure.ac (XE_EXPAND_VARIABLE):
diff -r 32f4ae21abc5 configure.ac
--- a/configure.ac	Tue May 05 12:45:20 2015 +0900
+++ b/configure.ac	Tue May 05 13:04:26 2015 +0900
@@ -5886,7 +5886,7 @@
 if test -n "$gcc_compiler_specs"; then
   echo "    - GCC specs file:                $gcc_compiler_specs"
 fi
-echo "    - Compiler command:              $XEMACS_CC $XE_CFLAGS"
+echo "    - Compiler command:              $XEMACS_CC $c_switch_all"
 if test "$CC" != "$XEMACS_CC"; then
   echo "  Compiler version for lib-src:      (detection code unimplemented)"
   echo "    - Compiler command for lib-src:  $CC $CFLAGS"