Handling i686 architecture in makefiles for clang.

[nishanth-kottary]

Summary

This is a part of D12316. Added i686 names for 32bit runtime configs so that built files will have the appropriate names.

[samsonov]

See my comment in a different CL - I would strongly prefer to not touch autoconf build system unless absolutely necessary.

runtime/compiler-rt/Makefile

     $(1) $$cflags $(2) -o /dev/null > /dev/null 2> /dev/null ; \
     echo $$?)
 
+# Finding CompilerTargetArch copied from clang_linux.mk
+CompilerTargetTriple := $(shell \
+  LANG=C $(CC) -v 2>&1 | grep 'Target:' | cut -d' ' -f2)
+ifeq ($(CompilerTargetTriple),)
+$(error "unable to infer compiler target triple for $(CC)")
+endif
+
+# Define configs only if arch in triple is i386 or x86_64
+CompilerTargetArch := $(firstword $(subst -, ,$(CompilerTargetTriple)))
+
 # We try to build 32-bit runtimes both on 32-bit hosts and 64-bit hosts.
-Runtime32BitConfigs = \
+Runtime32Bit-i386Configs = \
   builtins-i386.a profile-i386.a
+Runtime32Bit-i686Configs = \
+  builtins-i686.a profile-i686.a
 
 # We currently only try to generate runtime libraries on x86.
 ifeq ($(ARCH),x86)
-RuntimeLibrary.linux.Configs += $(Runtime32BitConfigs)
+ifeq ($(CompilerTargetArch), i386)
+RuntimeLibrary.linux.Configs += $(Runtime32Bit-i386Configs)
+else ifeq ($(CompilerTargetArch), i686)
+RuntimeLibrary.linux.Configs += $(Runtime32Bit-i686Configs)
+endif
 endif
 
 ifeq ($(ARCH),x86_64)

 # executable.
 test_source = $(LLVM_SRC_ROOT)/tools/clang/runtime/compiler-rt/clang_linux_test_input.c
 ifeq ($(call TryCompile,$(ToolDir)/clang,$(test_source),-m32),0)
-RuntimeLibrary.linux.Configs += $(Runtime32BitConfigs)
+RuntimeLibrary.linux.Configs += $(Runtime32Bit-i386Configs)
 endif
 endif