use $(shell uname) instead of $GOOS when

deciding what the host process support is.
this makes a cross-compiling (e.g., GOOS=nacl) build
still generate valid host debugger binaries.

R=r
DELTA=5  (0 added, 0 deleted, 5 changed)
OCL=34878
CL=34889

src/cmd/cov/Makefile

@@ -22,7 +22,7 @@ $(TARG): $(OFILES)
 clean:
 	rm -f $(OFILES) $(TARG)
 
-install: install-$(GOOS)
+install: install-$(shell uname | tr A-Z a-z)
 install-linux: install-default
 
 # on Darwin, have to install and setgid; see $GOROOT/src/sudo.bash

src/cmd/prof/Makefile

@@ -22,7 +22,7 @@ $(TARG): $(OFILES)
 clean:
 	rm -f $(OFILES) $(TARG)
 
-install: install-$(GOOS)
+install: install-$(shell uname | tr A-Z a-z)
 install-linux: install-default
 
 # on Darwin, have to install and setgid; see $GOROOT/src/sudo.bash

src/libmach/Makefile

@@ -45,7 +45,7 @@ OFILES=\
 	5obj.$O\
 	6obj.$O\
 	8obj.$O\
-	$(GOOS).$O\
+	$(shell uname | tr A-Z a-z).$O\
 
 HFILES=$(GOROOT)/include/mach.h elf.h macho.h obj.h