diff --git a/src/libcgo/Makefile b/src/libcgo/Makefile
index ff928f14cd4..380bc596e9d 100755
--- a/src/libcgo/Makefile
+++ b/src/libcgo/Makefile
@@ -2,10 +2,7 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
-# ugly hack to deal with whitespaces in $GOROOT
-nullstring :=
-space := $(nullstring) # a space at the end
-QUOTED_GOROOT=$(subst $(space),\ ,$(GOROOT))
+include ../Make.inc
 
 all: libcgo.so
 
@@ -16,9 +13,8 @@ OFILES=\
 	$(GOARCH).o\
 	util.o\
 
-CFLAGS_386=-m32
-CFLAGS_amd64=-m64
-
+HOST_CFLAGS_386=-m32
+HOST_CFLAGS_amd64=-m64
 
 LDFLAGS_linux=-shared -lpthread -lm
 LDFLAGS_darwin=-dynamiclib -Wl,-undefined,dynamic_lookup /usr/lib/libpthread.dylib
@@ -26,13 +22,13 @@ LDFLAGS_freebsd=-pthread -shared -lm
 LDFLAGS_windows=-shared -lm -mthreads
 
 %.o: %.c
-	$(CC) $(CFLAGS_$(GOARCH)) -g -O2 -fPIC -o $@ -c $*.c
+	$(HOST_CC) $(HOST_CFLAGS_$(GOARCH)) -g -O2 -fPIC -o $@ -c $*.c
 
 %.o: %.S
-	$(CC) $(CFLAGS_$(GOARCH)) -g -O2 -fPIC -o $@ -c $*.S
+	$(HOST_CC) $(HOST_CFLAGS_$(GOARCH)) -g -O2 -fPIC -o $@ -c $*.S
 
 libcgo.so: $(OFILES)
-	$(CC) $(CFLAGS_$(GOARCH)) -o libcgo.so $(OFILES) $(LDFLAGS_$(GOOS))
+	$(HOST_CC) $(HOST_CFLAGS_$(GOARCH)) -o libcgo.so $(OFILES) $(LDFLAGS_$(GOOS))
 
 $(QUOTED_GOROOT)/pkg/$(GOOS)_$(GOARCH)/libcgo.so: libcgo.so
 	cp libcgo.so $(QUOTED_GOROOT)/pkg/$(GOOS)_$(GOARCH)
diff --git a/src/libcgo/darwin_amd64.c b/src/libcgo/darwin_amd64.c
index 9d7255fbd5f..59fff059aeb 100644
--- a/src/libcgo/darwin_amd64.c
+++ b/src/libcgo/darwin_amd64.c
@@ -56,7 +56,7 @@ inittls(void)
 			fprintf(stderr, "\twanted 0x108 and 0x109\n");
 			fprintf(stderr, "\tgot");
 			for(i=0; i<ntofree; i++)
-				fprintf(stderr, " %#x", tofree[i]);
+				fprintf(stderr, " %#x", (unsigned)tofree[i]);
 			fprintf(stderr, "\n");
 			abort();
 		}
@@ -78,7 +78,7 @@ inittls(void)
 	asm volatile("movq %%gs:0x8a8, %0" : "=r"(y));
 
 	if(x != 0x123456789abcdef0ULL || y != 0x0fedcba987654321) {
-		printf("libcgo: thread-local storage %#x not at %%gs:0x8a0 - x=%#llx y=%#llx\n", k1, x, y);
+		printf("libcgo: thread-local storage %#x not at %%gs:0x8a0 - x=%#llx y=%#llx\n", (unsigned)k1, x, y);
 		abort();
 	}
 }