--- a/src/libmach/Makefile
+++ b/src/libmach/Makefile
@@ -49,15 +49,8 @@ OFILES=\
 	6obj.$O\
 	8obj.$O\
 
-ifneq ($(GOHOSTOS),windows)
 OFILES+=\
-	$(shell uname | tr A-Z a-z).$O\
-
-else
-OFILES+=\
-	windows.$O\
-
-endif
+	$(GOOS).$O\
 
 HFILES=../../include/mach.h elf.h macho.h obj.h
 
--- a/src/cmd/cov/Makefile
+++ b/src/cmd/cov/Makefile
@@ -23,11 +23,7 @@ LIB=\
 NOINSTALL=1
 include ../../Make.ccmd
 
-ifeq ($(GOOS),windows)
-NAME=windows
-else
-NAME=$(shell uname | tr A-Z a-z)
-endif
+NAME=$(GOOS)
 
 install: install-$(NAME)
 install-linux: install-default
--- a/src/cmd/prof/Makefile
+++ b/src/cmd/prof/Makefile
@@ -19,11 +19,7 @@ LIB=\
 NOINSTALL=1
 include ../../Make.ccmd
 
-ifeq ($(GOOS),windows)
-NAME=windows
-else
-NAME=$(shell uname | tr A-Z a-z)
-endif
+NAME=$(GOOS)
 
 install: install-$(NAME) install-pprof
 install-linux: install-default
--- a/src/pkg/syscall/mkerrors.sh
+++ b/src/pkg/syscall/mkerrors.sh
@@ -13,9 +13,7 @@ export LC_CTYPE=C
 
 GCC=gcc
 
-uname=$(uname)
-
-includes_Linux='
+includes_linux='
 #define _LARGEFILE_SOURCE
 #define _LARGEFILE64_SOURCE
 #define _FILE_OFFSET_BITS 64
@@ -36,7 +34,7 @@ includes_Linux='
 #include <netpacket/packet.h>
 '
 
-includes_Darwin='
+includes_darwin='
 #define _DARWIN_C_SOURCE
 #define KERNEL
 #define _DARWIN_USE_64_BIT_INODE
@@ -54,7 +52,7 @@ includes_Darwin='
 #include <netinet/ip_mroute.h>
 '
 
-includes_FreeBSD='
+includes_freebsd='
 #include <sys/types.h>
 #include <sys/event.h>
 #include <sys/socket.h>
@@ -97,7 +95,7 @@ done
 
 # Write godefs input.
 (
-	indirect="includes_$(uname)"
+	indirect="includes_$(GOOS)"
 	echo "${!indirect} $includes"
 	echo
 	echo 'enum {'