Harden and adjust 'gcc/configure' parsing of '--enable-offload-targets'

Fix-up for commit d228ee80 "re PR
bootstrap/92314 (missing omp-device-properties', needed by
's-omp-device-properties-h')".

	gcc/
	* configure.ac <$enable_offload_targets>: Do parsing as done
	elsewhere.
	* configure: Regenerate.

gcc/ChangeLog

 2020-04-29  Thomas Schwinge  <thomas@codesourcery.com>
 
+	* configure.ac <$enable_offload_targets>: Do parsing as done
+	elsewhere.
+	* configure: Regenerate.
+
 	* configure.ac <$enable_offload_targets>: 'amdgcn' is 'gcn'.
 	* configure: Regenerate.
 

gcc/configure

@@ -7920,18 +7920,21 @@ for tgt in `echo $enable_offload_targets | sed 's/,/ /g'`; do
   else
     enable_offloading=1
     case "$tgt" in
-      *-intelmicemul-*)
+      *-intelmic-* | *-intelmicemul-*)
 	omp_device_property=omp-device-properties-i386
 	omp_device_property_tmake_file="${omp_device_property_tmake_file} \$(srcdir)/config/i386/t-omp-device"
 	;;
-      amdgcn*-*)
+      amdgcn*)
 	omp_device_property=omp-device-properties-gcn
 	omp_device_property_tmake_file="${omp_device_property_tmake_file} \$(srcdir)/config/gcn/t-omp-device"
 	;;
-      nvptx*-*)
+      nvptx*)
 	omp_device_property=omp-device-properties-nvptx
 	omp_device_property_tmake_file="${omp_device_property_tmake_file} \$(srcdir)/config/nvptx/t-omp-device"
 	;;
+      *)
+	as_fn_error $? "unknown offload target specified" "$LINENO" 5
+	;;
     esac
     omp_device_properties="${omp_device_properties} ${tgt}=${omp_device_property}"
     omp_device_property_deps="${omp_device_property_deps} ${omp_device_property}"
@@ -18985,7 +18988,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 18988 "configure"
+#line 18991 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -19091,7 +19094,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 19094 "configure"
+#line 19097 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H

gcc/configure.ac

@@ -1045,18 +1045,21 @@ for tgt in `echo $enable_offload_targets | sed 's/,/ /g'`; do
   else
     enable_offloading=1
     case "$tgt" in
-      *-intelmicemul-*)
+      *-intelmic-* | *-intelmicemul-*)
 	omp_device_property=omp-device-properties-i386
 	omp_device_property_tmake_file="${omp_device_property_tmake_file} \$(srcdir)/config/i386/t-omp-device"
 	;;
-      amdgcn*-*)
+      amdgcn*)
 	omp_device_property=omp-device-properties-gcn
 	omp_device_property_tmake_file="${omp_device_property_tmake_file} \$(srcdir)/config/gcn/t-omp-device"
 	;;
-      nvptx*-*)
+      nvptx*)
 	omp_device_property=omp-device-properties-nvptx
 	omp_device_property_tmake_file="${omp_device_property_tmake_file} \$(srcdir)/config/nvptx/t-omp-device"
 	;;
+      *)
+	AC_MSG_ERROR([unknown offload target specified])
+	;;
     esac
     omp_device_properties="${omp_device_properties} ${tgt}=${omp_device_property}"
     omp_device_property_deps="${omp_device_property_deps} ${omp_device_property}"