--- a/js/src/Makefile.in
+++ b/js/src/Makefile.in
@@ -55,17 +55,17 @@ DIRS += editline
 endif
 
 # editline needs to get built before the shell
 ifndef JS_DISABLE_SHELL
 DIRS += shell
 endif
 
 # FIXME: bug 530688 covers getting these working on Android
-ifneq (,$(filter-out ANDROID,$(OS_ARCH)))
+ifneq ($(OS_ARCH),ANDROID)
 ifdef ENABLE_TESTS
 DIRS += jsapi-tests
 endif
 endif
 
 ifdef ENABLE_TESTS
 DIRS += tests
 endif
@@ -490,17 +490,17 @@ VPATH += $(srcdir)/perf
 INSTALLED_HEADERS += jsperf.h
 CPPSRCS += jsperf.cpp
 ifdef HAVE_LINUX_PERF_EVENT_H
 CPPSRCS += pm_linux.cpp
 else
 CPPSRCS += pm_stub.cpp
 endif
 
-ifeq (,$(filter-out WINNT,$(OS_ARCH)))
+ifeq ($(OS_ARCH),WINNT)
 INSTALLED_HEADERS += jscpucfg.h
 endif
 
 EXPORTS = $(INSTALLED_HEADERS)
 
 DASH_R		= -r
 
 ifneq (,$(filter OS2 WINNT,$(OS_ARCH)))
@@ -532,17 +532,17 @@ ifneq ($(OS_ARCH),Darwin)
 DTRACE_PROBE_OBJ = $(LIBRARY_NAME)-dtrace.$(OBJ_SUFFIX)
 endif
 MOZILLA_DTRACE_SRC = $(srcdir)/javascript-trace.d
 endif
 
 default::
 
 ifneq (,$(CROSS_COMPILE)$(filter-out WINNT OS2,$(OS_ARCH)))
-ifneq (,$(filter-out SYMBIAN,$(OS_ARCH)))
+ifneq ($(OS_ARCH),SYMBIAN)
 # nsinstall doesn't get built until we enter config/ in the exports phase,
 # so we'll have to manually ensure it gets built here if we want to use
 # $(EXPORTS)
 export:: config/nsinstall$(HOST_BIN_SUFFIX)
 $(PUBLIC) $(SDK_PUBLIC): config/nsinstall$(HOST_BIN_SUFFIX)
 
 config/nsinstall$(HOST_BIN_SUFFIX): $(srcdir)/config/nsinstall.c $(srcdir)/config/pathsub.c
 	$(MAKE) -C config/ nsinstall$(HOST_BIN_SUFFIX)