Re-enable support for --program-prefix.

The Apple buildbots have been modified not to pass --target,
so they shouldn't choke on a default program prefix anymore.

Patch by Rick Foos!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164956 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/configure b/configure
index 1905537..e9ab6bc 100755
--- a/configure
+++ b/configure
@@ -790,6 +790,7 @@
 ENABLE_VISIBILITY_INLINES_HIDDEN
 RPATH
 RDYNAMIC
+program_prefix
 LIBOBJS
 LTLIBOBJS'
 ac_subst_files=''
@@ -10312,7 +10313,7 @@
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<EOF
-#line 10315 "configure"
+#line 10316 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -21127,6 +21128,10 @@
 ac_config_files="$ac_config_files bindings/ocaml/llvm/META.llvm"
 
 
+test "x$program_prefix" = "xNONE" && program_prefix=""
+
+
+
 ac_config_commands="$ac_config_commands setup"
 
 ac_config_commands="$ac_config_commands Makefile"
@@ -22050,11 +22055,12 @@
 ENABLE_VISIBILITY_INLINES_HIDDEN!$ENABLE_VISIBILITY_INLINES_HIDDEN$ac_delim
 RPATH!$RPATH$ac_delim
 RDYNAMIC!$RDYNAMIC$ac_delim
+program_prefix!$program_prefix$ac_delim
 LIBOBJS!$LIBOBJS$ac_delim
 LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
-  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 93; then
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 94; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5