Revert "Fix NSS parallel build"

For whatever reason this now fails on Windows for multiple
users (including myself). Doesn't look like an easy fix is
possible, so this is reverted until I find some more time
to look into it (or give up on it).

This reverts commit baf0d6d6.

Change-Id: I432637131ba8ac8be614496bd6da0e157372ae94
Reviewed-on: https://gerrit.libreoffice.org/63664Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
Tested-by: Jan-Marek Glogowski <glogow@fbihome.de>

external/nss/ExternalProject_nss.mk

@@ -23,7 +23,7 @@ $(call gb_ExternalProject_get_state_target,nss,build): $(call gb_ExternalExecuta
 		$(if $(filter X86_64,$(CPUNAME)),USE_64=1) \
 		LIB="$(ILIB)" \
 		XCFLAGS="-arch:SSE $(SOLARINC)" \
-		$(MAKE) nss_build_all RC="rc.exe $(SOLARINC)" \
+		$(MAKE) -j1 nss_build_all RC="rc.exe $(SOLARINC)" \
 			NSINSTALL='$(call gb_ExternalExecutable_get_command,python) $(SRCDIR)/external/nss/nsinstall.py' \
 	,nss)
 
@@ -45,7 +45,7 @@ $(call gb_ExternalProject_get_state_target,nss,build): $(call gb_ExternalExecuta
 			$(if $(filter iOS-ARM,$(OS)-$(CPUNAME)),CPU_ARCH=arm) \
 			NSPR_CONFIGURE_OPTS="--build=$(BUILD_PLATFORM) --host=$(HOST_PLATFORM)") \
 		NSDISTMODE=copy \
-		$(MAKE) AR="$(AR)" \
+		$(MAKE) -j1 AR="$(AR)" \
 			RANLIB="$(RANLIB)" \
 			NMEDIT="$(NM)edit" \
 			COMMA=$(COMMA) \

external/nss/UnpackedTarball_nss.mk

@@ -34,7 +34,6 @@ $(eval $(call gb_UnpackedTarball_add_patches,nss,\
     	external/nss/nss.utf8bom.patch.1) \
 	$(if $(filter ANDROID,$(OS)), \
 		external/nss/nss-android.patch.1) \
-	external/nss/nss.parallel.patch \
 ))
 
 ifeq ($(COM_IS_CLANG),TRUE)