Add "dependencies" target to top-level Makefile

Makefile

 # Copyright 2011 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 52 matching lines @@
   GYPFLAGS += -Dv8_use_liveobjectlist=true
 endif
 # vfp3=off
 ifeq ($(vfp3), off)
   GYPFLAGS += -Dv8_can_use_vfp_instructions=false
 else
   GYPFLAGS += -Dv8_can_use_vfp_instructions=true
 endif
 
 # ----------------- available targets: --------------------
+# - "dependencies": pulls in external dependencies (currently: GYP)
 # - any arch listed in ARCHES (see below)
 # - any mode listed in MODES
 # - every combination <arch>.<mode>, e.g. "ia32.release"
 # - any of the above with .check appended, e.g. "ia32.release.check"
 # - default (no target specified): build all ARCHES and MODES
 # - "check": build all targets and run all tests
 # - "<arch>.clean" for any <arch> in ARCHES
 # - "clean": clean all ARCHES
 
 # ----------------- internal stuff ------------------------
 
 # Architectures and modes to be compiled. Consider these to be internal
 # variables, don't override them (use the targets instead).
 ARCHES = ia32 x64 arm
 MODES = release debug
 
 # List of files that trigger Makefile regeneration:
 GYPFILES = build/all.gyp build/common.gypi build/standalone.gypi \
            preparser/preparser.gyp samples/samples.gyp src/d8.gyp \
            test/cctest/cctest.gyp tools/gyp/v8.gyp
 
 # Generates all combinations of ARCHES and MODES, e.g. "ia32.release".
 BUILDS = $(foreach mode,$(MODES),$(addsuffix .$(mode),$(ARCHES)))
 # Generates corresponding test targets, e.g. "ia32.release.check".
 CHECKS = $(addsuffix .check,$(BUILDS))
 # File where previously used GYPFLAGS are stored.
 ENVFILE = $(OUTDIR)/environment
 
-.PHONY: all check clean $(ENVFILE).new \
+.PHONY: all check clean dependencies $(ENVFILE).new \
         $(ARCHES) $(MODES) $(BUILDS) $(CHECKS) $(addsuffix .clean,$(ARCHES)) \
         $(addsuffix .check,$(MODES)) $(addsuffix .check,$(ARCHES))
 
 # Target definitions. "all" is the default.
 all: $(MODES)
 
 # Compile targets. MODES and ARCHES are convenience targets.
 .SECONDEXPANSION:
 $(MODES): $(addsuffix .$$@,$(ARCHES))
 
@@ skipping 51 matching lines @@
 # Replaces the old with the new environment file if they're different, which
 # will trigger GYP to regenerate Makefiles.
 $(ENVFILE): $(ENVFILE).new
         @if test -r $(ENVFILE) && cmp $(ENVFILE).new $(ENVFILE) >/dev/null; \
             then rm $(ENVFILE).new; \
             else mv $(ENVFILE).new $(ENVFILE); fi
 
 # Stores current GYPFLAGS in a file.
 $(ENVFILE).new:
         @mkdir -p $(OUTDIR); echo "GYPFLAGS=$(GYPFLAGS)" > $(ENVFILE).new;
+
+# Dependencies.
+dependencies:
+        svn checkout --force http://gyp.googlecode.com/svn/trunk build/gyp \
+            --revision 1026