let clang build llvm, fix rustllvm linking error

Author: crabtw

configure

@@ -536,14 +536,25 @@ do
 	# Disable unused LLVM features
 	LLVM_OPTS="$LLVM_DBG_OPTS --disable-docs --disable-jit --enable-bindings=none --disable-threads --disable-pthreads"
 
-	LLVM_CXX_32="g++ -m32"
-	LLVM_CC_32="gcc -m32"
+        if [ "$CFG_C_COMPILER" = "clang" ]
+        then
+	    LLVM_CXX_32="clang++ -m32"
+	    LLVM_CC_32="clang -m32"
+
+	    LLVM_CXX_64="clang++"
+	    LLVM_CC_64="clang"
+        else
+	    LLVM_CXX_32="g++ -m32"
+	    LLVM_CC_32="gcc -m32"
+
+	    LLVM_CXX_64="g++"
+	    LLVM_CC_64="gcc"
+        fi
+
 	LLVM_CFLAGS_32="-m32"
 	LLVM_CXXFLAGS_32="-m32"
 	LLVM_LDFLAGS_32="-m32"
 
-	LLVM_CXX_64="g++"
-	LLVM_CC_64="gcc"
 	LLVM_CFLAGS_64=""
 	LLVM_CXXFLAGS_64=""
 	LLVM_LDFLAGS_64=""

mk/rustllvm.mk

@@ -37,7 +37,7 @@ rustllvm/$(1)/$(CFG_RUSTLLVM): $$(RUSTLLVM_OBJS_OBJS_$(1)) \
 
 rustllvm/$(1)/%.o: rustllvm/%.cpp $$(MKFILE_DEPS) $$(LLVM_CONFIG_$(1))
 	@$$(call E, compile: $$@)
-	$$(Q)$$(call CFG_COMPILE_C_$(1), $$@, $$(LLVM_CXXFLAGS_$(1)) $$(RUSTLLVM_INCS_$(1))) $$<
+	$$(Q)$$(call CFG_COMPILE_C_$(1), $$@, $$(subst -I, -iquote , $$(LLVM_CXXFLAGS_$(1))) $$(RUSTLLVM_INCS_$(1))) $$<
 endef
 
 # Instantiate template for all stages