Get codebase completely working with LLVM

You can now build Cosmopolitan with Clang:

    make -j8 MODE=llvm
    o/llvm/examples/hello.com

The assembler and linker code is now friendly to LLVM too.
So it's not needed to configure Clang to use binutils under
the hood. If you love LLVM then you can now use pure LLVM.

build/config.mk

@@ -20,8 +20,6 @@ CONFIG_CCFLAGS +=		\
 TARGET_ARCH ?=			\
 	-msse3
 
-RAGELFLAGS ?= -G2
-
 endif
 
 # Optimized Mode
@@ -48,8 +46,6 @@ CONFIG_CCFLAGS +=		\
 TARGET_ARCH ?=			\
 	-march=native
 
-RAGELFLAGS ?= -G2
-
 endif
 
 # Release Mode
@@ -73,8 +69,6 @@ CONFIG_CCFLAGS +=		\
 	$(BACKTRACES)		\
 	-O2
 
-RAGELFLAGS = -G2
-
 endif
 
 # Debug Mode
@@ -247,6 +241,23 @@ TARGET_ARCH ?=			\
 	-msse3
 endif
 
+# LLVM Mode
+ifeq ($(MODE), llvm)
+TARGET_ARCH ?= -msse3
+CONFIG_CCFLAGS += $(BACKTRACES) $(FTRACE) -O2
+AS = clang
+CC = clang
+CXX = clang++
+CXXFILT = llvm-c++filt
+LD = ld.lld
+NM = llvm-nm
+GCC = clang
+STRIP = llvm-strip
+OBJCOPY = llvm-objcopy
+OBJDUMP = llvm-objdump
+ADDR2LINE = llvm-addr2line
+endif
+
 # ANSI Mode
 #
 # These flags cause GCC to predefine __STRICT_ANSI__. Please be warned