When passing CC or CXX down to sub-makes, add quotes around it so that

blanks (say, CC=ccache distcc gcc -m64) don't mess things up.

src/leveldb/Makefile

@@ -12,7 +12,7 @@ OPT ?= -O2 -DNDEBUG       # (A) Production use (optimized mode)
 #-----------------------------------------------
 
 # detect what platform we're building on
-$(shell CC=$(CC) CXX=$(CXX) TARGET_OS=$(TARGET_OS) \
+$(shell CC="$(CC)" CXX="$(CXX)" TARGET_OS=$(TARGET_OS) \
     ./build_detect_platform build_config.mk ./)
 # this file is generated by the previous line to set build flags and sources
 include build_config.mk

src/makefile.unix

@@ -170,7 +170,7 @@ LIBS += $(CURDIR)/leveldb/libleveldb.a $(CURDIR)/leveldb/libmemenv.a
 DEFS += $(addprefix -I,$(CURDIR)/leveldb/include)
 DEFS += $(addprefix -I,$(CURDIR)/leveldb/helpers)
 leveldb/libleveldb.a:
-	@echo "Building LevelDB ..." && cd leveldb && $(MAKE) CC=$(CC) CXX=$(CXX) OPT="$(xCXXFLAGS)" libleveldb.a libmemenv.a && cd ..
+	@echo "Building LevelDB ..." && cd leveldb && $(MAKE) CC="$(CC)" CXX="$(CXX)" OPT="$(xCXXFLAGS)" libleveldb.a libmemenv.a && cd ..
 
 #
 # libtorrent hack
@@ -183,7 +183,7 @@ DEFS += -DTORRENT_DEBUG
 DEFS += -DBOOST_ASIO_SEPARATE_COMPILATION
 #DEFS += -DBOOST_ASIO_DYN_LINK
 ../libtorrent/src/.libs/libtorrent-rasterbar.a:
-	@echo "Building libtorrent ..." && cd ../libtorrent && $(MAKE) CC=$(CC) CXX=$(CXX) OPT="$(xCXXFLAGS)" && cd ../src
+	@echo "Building libtorrent ..." && cd ../libtorrent && $(MAKE) CC="$(CC)" CXX="$(CXX)" OPT="$(xCXXFLAGS)" && cd ../src
 
 
 # auto-generated dependencies: