[build] Ensure target_arch is set correctly in toplevel Makefile

Makefile

Index: Makefile
diff --git a/Makefile b/Makefile
index b2e6753bed116d8d2053a77e52888fd089518144..501d0c80eafa3d041bea35cd9e7bf69d8dc49cf4 100644
--- a/Makefile
+++ b/Makefile
@@ -252,6 +252,7 @@ endif
 # variables, don't override them (use the targets instead).
 ARCHES = ia32 x64 x32 arm arm64 mips mipsel mips64 mips64el x87 ppc ppc64 \
 		 s390 s390x
+ARCHES32 = ia32 x32 arm mips mipsel x87 ppc s390

[Michael Achenbach, 2016/06/08 13:22:18]

Not sure if simulation of x32 would require target_arch=ia32? It's this 32 bit
user space in a 64 bit system, how would a simulator run. Do we even have one? I
think we recently dropped support for x32.

[jochen (gone - plz use gerrit), 2016/06/08 13:24:28]

yeah, x32 should be deleted

 DEFAULT_ARCHES = ia32 x64 arm
 MODES = release debug optdebug
 DEFAULT_MODES = release debug
@@ -454,7 +455,9 @@ $(OUT_MAKEFILES): $(GYPFILES) $(ENVFILE)
 	              -Igypfiles/standalone.gypi --depth=. \
 	              -Dv8_target_arch=$(V8_TARGET_ARCH) \
 	              $(if $(findstring $(CXX_TARGET_ARCH),$(V8_TARGET_ARCH)), \
-	              -Dtarget_arch=$(V8_TARGET_ARCH),) \
+	              -Dtarget_arch=$(V8_TARGET_ARCH), \
+	                  $(if $(shell echo $(ARCHES32) | grep $(V8_TARGET_ARCH)), \
+	                  -Dtarget_arch=ia32,)) \

[Michael Achenbach, 2016/06/08 13:22:18]

Using ia32 is a simplification. Theoretically we'd need the 32 bit version of
CXX_TARGET_ARCH. But whoever needs this is welcome to deliver a better patch... 

 	              $(if $(findstring optdebug,$@),-Dv8_optimized_debug=1,) \
 	              -S$(suffix $(basename $@))$(suffix $@) $(GYPFLAGS)