[Ada] clean ups in Makefiles

[Arnaud Charlet <charlet@adacore.com>]

This patch cleans up makefile targets related to the generation of
s-oscons.ads. We had duplicate rules between Make-generated.in and
gcc-interface/Makefile.in which caused confusion recently and are now removed.
The rules are now handled in Make-generated.in only, as was intended when
Make-generated.in was introduced. A few minor clean ups also done while
reviewing these files.

Tested on x86_64-pc-linux-gnu, committed on trunk.

libada/                                             
	* Makefile.in (osconstool): Fix target.     
ada/
	* gcc-interface/Makefile.in, gcc-interface/Make-lang.in: Remove
	duplicate rules handled by Make-generated.in.
--
Index: libada/Makefile.in
===================================================================
--- libada/Makefile.in	(revision 193034)
+++ libada/Makefile.in	(working copy)
@@ -113,7 +113,7 @@ gnatlib-sjlj gnatlib-zcx gnatlib-shared:
 	$(LN_S) $(ADA_RTS_DIR) adalib
 
 osconstool:
-	$(MAKE) -C $(GCC_DIR)/ada $(LIBADA_FLAGS_TO_PASS) ./bldtools/oscons/xoscons
+	$(MAKE) -C $(GCC_DIR) $(LIBADA_FLAGS_TO_PASS) ada/s-oscons.ads
 
 install-gnatlib: $(GCC_DIR)/ada/Makefile
 	$(MAKE) -C $(GCC_DIR)/ada $(LIBADA_FLAGS_TO_PASS) install-gnatlib
Index: gcc/ada/gcc-interface/Makefile.in
===================================================================
--- gcc/ada/gcc-interface/Makefile.in	(revision 193208)
+++ gcc/ada/gcc-interface/Makefile.in	(working copy)
@@ -2577,48 +2577,13 @@ install-gnatlib: ../stamp-gnatlib-$(RTSD
 	                $(RTSDIR)/$(word 1,$(subst <, ,$(PAIR)));)
 # Copy tsystem.h
 	$(CP) $(srcdir)/tsystem.h $(RTSDIR)
+# Copy generated target dependent sources
+	$(RM) $(RTSDIR)/s-oscons.ads
+	(cd $(RTSDIR); $(LN_S) ../s-oscons.ads s-oscons.ads)
 	$(RM) ../stamp-gnatlib-$(RTSDIR)
 	touch ../stamp-gnatlib1-$(RTSDIR)
 
-ifeq ($(strip $(filter-out alpha64 ia64 dec hp vms% openvms% alphavms%,$(subst -, ,$(host)))),)
-OSCONS_CPP=../../$(DECC) -E /comment=as_is -DNATIVE \
-             -DTARGET='""$(target)""' $(fsrcpfx)ada/s-oscons-tmplt.c
-
-OSCONS_EXTRACT=../../$(DECC) -DNATIVE \
-                 -DTARGET='""$(target)""' $(fsrcpfx)ada/s-oscons-tmplt.c ; \
-  ld -o s-oscons-tmplt.exe s-oscons-tmplt.obj; \
-  ./s-oscons-tmplt.exe > s-oscons-tmplt.s
-
-else
-# GCC_FOR_TARGET has paths relative to the gcc directory, so we need to adjust
-# for running it from $(RTSDIR)
-OSCONS_CC=`echo "$(GCC_FOR_TARGET)" \
-  | sed -e 's^\./xgcc^../../xgcc^' -e 's^-B./^-B../../^'`
-OSCONS_CPP=$(OSCONS_CC) $(GNATLIBCFLAGS) -E -C \
-  -DTARGET=\"$(target)\" $(fsrcpfx)ada/s-oscons-tmplt.c > s-oscons-tmplt.i
-OSCONS_EXTRACT=$(OSCONS_CC) $(GNATLIBCFLAGS) -S s-oscons-tmplt.i
-endif
-
-./bldtools/oscons/xoscons: xoscons.adb xutil.ads xutil.adb
-	-$(MKDIR) ./bldtools/oscons
-	$(RM) $(addprefix ./bldtools/oscons/,$(notdir $^))
-	$(CP) $^ ./bldtools/oscons
-	(cd ./bldtools/oscons ; gnatmake -q xoscons)
-
-$(RTSDIR)/s-oscons.ads: ../stamp-gnatlib1-$(RTSDIR) s-oscons-tmplt.c gsocket.h ./bldtools/oscons/xoscons
-	$(RM) $(RTSDIR)/s-oscons-tmplt.i $(RTSDIR)/s-oscons-tmplt.s
-	(cd $(RTSDIR) ; \
-	    $(OSCONS_CPP) ; \
-	    $(OSCONS_EXTRACT) ; \
-	    ../bldtools/oscons/xoscons s-oscons)
-
-# Don't use semicolon separated shell commands that involve list expansions.
-# The semicolon triggers a call to DCL on VMS and DCL can't handle command
-# line lengths in excess of 256 characters.
-# Example: cd $(RTSDIR); ar rc libfoo.a $(LONG_LIST_OF_OBJS)
-# is guaranteed to overflow the buffer.
-
-gnatlib: ../stamp-gnatlib1-$(RTSDIR) ../stamp-gnatlib2-$(RTSDIR) $(RTSDIR)/s-oscons.ads
+gnatlib: ../stamp-gnatlib1-$(RTSDIR) ../stamp-gnatlib2-$(RTSDIR)
 # C files
 	$(MAKE) -C $(RTSDIR) \
 		CC="`echo \"$(GCC_FOR_TARGET)\" \
Index: gcc/ada/gcc-interface/Make-lang.in
===================================================================
--- gcc/ada/gcc-interface/Make-lang.in	(revision 193208)
+++ gcc/ada/gcc-interface/Make-lang.in	(working copy)
@@ -122,7 +122,7 @@ ifeq ($(build), $(host))
 
     # put the host RTS dir first in the PATH to hide the default runtime
     # files that are among the sources
-    RTS_DIR=$(strip $(subst \,/,$(shell gnatls -v | grep adalib )))
+    RTS_DIR:=$(strip $(subst \,/,$(shell gnatls -v | grep adalib )))
 
     ADA_TOOLS_FLAGS_TO_PASS=\
         CC="$(CC)" \
@@ -157,7 +157,7 @@ else
   else
     # This is a canadian cross. We should use a toolchain running on the
     # build platform and targeting the host platform.
-    RTS_DIR=$(strip $(subst \,/,$(shell $(GNATLS_FOR_HOST) -v | grep adalib )))
+    RTS_DIR:=$(strip $(subst \,/,$(shell $(GNATLS_FOR_HOST) -v | grep adalib )))
     ADA_TOOLS_FLAGS_TO_PASS=\
         CC="$(CC)" \
         $(COMMON_FLAGS_TO_PASS) $(ADA_FLAGS_TO_PASS)  \
@@ -574,7 +574,7 @@ canadian-gnattools: force
 	$(MAKE) -C ada $(ADA_TOOLS_FLAGS_TO_PASS) gnattools2
 	$(MAKE) -C ada $(ADA_TOOLS_FLAGS_TO_PASS) gnattools4
 
-gnatlib gnatlib-sjlj gnatlib-zcx gnatlib-shared: force
+gnatlib gnatlib-sjlj gnatlib-zcx gnatlib-shared: ada/s-oscons.ads force
 	$(MAKE) -C ada $(COMMON_FLAGS_TO_PASS)  \
 	   GNATLIBFLAGS="$(GNATLIBFLAGS)" \
 	   GNATLIBCFLAGS="$(GNATLIBCFLAGS)" \