When using "make VERBOSE=1", make sure compiler-rt is also build verbosely.

[Jean-Daniel]

Summary

When building clang+compiler-rt verbosely, the build commands of compiler-rt are not output in the terminal as expected.
This patch fixes the issue by forwarding the VERBOSE flag to the compiler-rt make.

[• villmow]

Why not just do:
VERBOSE ?= $(VERBOSE)

Wondering why a new variable needs to be created here.

[• villmow]

actually that doesn't make sense, why not just use $(VERBOSE) instead of $(RUNTIME_VERBOSE) in the make rule?

[Jean-Daniel]

Because I erroneously though that simply using "make VERBOSE=" was enough to enable verbose mode.

runtime/compiler-rt/Makefile

 # We build all the libraries in a single shot to avoid recursive make as much as
 # possible.
 BuildRuntimeLibraries:
   $(Verb) $(MAKE) -C $(COMPILERRT_SRC_ROOT) \
     ProjSrcRoot=$(COMPILERRT_SRC_ROOT) \
     ProjObjRoot=$(PROJ_OBJ_DIR) \
     CC="$(ToolDir)/clang" \
     LLVM_ANDROID_TOOLCHAIN_DIR="$(LLVM_ANDROID_TOOLCHAIN_DIR)" \
+    VERBOSE=$(VERBOSE) \
     $(RuntimeDirs:%=clang_%)
 .PHONY: BuildRuntimeLibraries
 CleanRuntimeLibraries:
   $(Verb) $(MAKE) -C $(COMPILERRT_SRC_ROOT) \
     ProjSrcRoot=$(COMPILERRT_SRC_ROOT) \
     ProjObjRoot=$(PROJ_OBJ_DIR) \
+    VERBOSE=$(VERBOSE) \
     clean
 .PHONY: CleanRuntimeLibraries
 
 $(PROJ_resources_lib):
   $(Verb) $(MKDIR) $@
 
 # Expand rules for copying/installing each individual library. We can't use
 # implicit rules here because we need to match against multiple things.