--- a/config/config.mk
+++ b/config/config.mk
@@ -410,31 +410,21 @@ GARBAGE		+= $(DEPENDENCIES) core $(wildc
 ifeq ($(OS_ARCH),Darwin)
 ifndef NSDISTMODE
 NSDISTMODE=absolute_symlink
 endif
 PWD := $(CURDIR)
 endif
 
 NSINSTALL_PY := $(PYTHON) $(abspath $(MOZILLA_DIR)/config/nsinstall.py)
-# For Pymake, wherever we use nsinstall.py we're also going to try to make it
-# a native command where possible. Since native commands can't be used outside
-# of single-line commands, we continue to provide INSTALL for general use.
-# Single-line commands should be switched over to install_cmd.
-NSINSTALL_NATIVECMD := %nsinstall nsinstall
-
-ifdef NSINSTALL_BIN
-NSINSTALL = $(NSINSTALL_BIN)
-else
-ifeq ($(HOST_OS_ARCH),WINNT)
+ifneq (,$(or $(filter WINNT,$(HOST_OS_ARCH)),$(if $(COMPILE_ENVIRONMENT),,1)))
 NSINSTALL = $(NSINSTALL_PY)
 else
 NSINSTALL = $(DEPTH)/config/nsinstall$(HOST_BIN_SUFFIX)
 endif # WINNT
-endif # NSINSTALL_BIN
 
 
 ifeq (,$(CROSS_COMPILE)$(filter-out WINNT, $(OS_ARCH)))
 INSTALL = $(NSINSTALL) -t
 
 else
 
 # This isn't laid out as conditional directives so that NSDISTMODE can be

--- a/js/src/old-configure.in
+++ b/js/src/old-configure.in
@@ -313,21 +313,16 @@ AC_SUBST(_MSC_VER)
 AC_SUBST(GNU_AS)
 AC_SUBST(GNU_LD)
 AC_SUBST(GNU_CC)
 AC_SUBST(GNU_CXX)
 
 dnl ========================================================
 dnl Checks for programs.
 dnl ========================================================
-if test -z "$COMPILE_ENVIRONMENT"; then
-    NSINSTALL_BIN='$(PYTHON) $(topsrcdir)/config/nsinstall.py'
-fi
-AC_SUBST(NSINSTALL_BIN)
-
 if test "$COMPILE_ENVIRONMENT"; then
 
 dnl ========================================================
 dnl = Mac OS X toolchain support
 dnl ========================================================
 
 dnl The universal machinery sets UNIVERSAL_BINARY to inform packager.mk
 dnl that a universal binary is being produced.

--- a/old-configure.in
+++ b/old-configure.in
@@ -470,21 +470,16 @@ AC_SUBST(GNU_CXX)
 
 AC_SUBST(STL_FLAGS)
 AC_SUBST(WRAP_STL_INCLUDES)
 AC_SUBST(MOZ_MSVC_STL_WRAP_RAISE)
 
 dnl ========================================================
 dnl Checks for programs.
 dnl ========================================================
-if test -z "$COMPILE_ENVIRONMENT"; then
-    NSINSTALL_BIN='$(PYTHON) $(MOZILLA_DIR)/config/nsinstall.py'
-fi
-AC_SUBST(NSINSTALL_BIN)
-
 if test "$COMPILE_ENVIRONMENT"; then
 
 dnl ========================================================
 dnl = Mac OS X toolchain support
 dnl ========================================================
 
 dnl The universal machinery sets UNIVERSAL_BINARY to inform packager.mk
 dnl that a universal binary is being produced.