Add dependency of dos unit to objpas unit due to use of objfpc mode for FreeRTOS OS

rtl/freertos/Makefile

@@ -892,6 +892,8 @@ endif
 CPU_UNITS=
 SYSINIT_UNITS=
 CPU_SPECIFIC_COMMON_UNITS=
+DOSDIR=.
+DOS_DEPS_OS=objpas$(PPUEXT)
 ifeq ($(ARCH),arm)
 CPU_SPECIFIC_COMMON_UNITS=sysutils math classes fgl macpas typinfo types rtlconsts getopts lineinfo
 ifeq ($(SUBARCH),armv7m)

rtl/freertos/Makefile.fpc

@@ -71,6 +71,11 @@ CPU_UNITS=
 SYSINIT_UNITS=
 CPU_SPECIFIC_COMMON_UNITS=
 
+# Dos unit, local source
+DOSDIR=.
+# Dos unit uses objfpc mode
+DOS_DEPS_OS=objpas$(PPUEXT)
+
 ifeq ($(ARCH),arm)
 CPU_SPECIFIC_COMMON_UNITS=sysutils math classes fgl macpas typinfo types rtlconsts getopts lineinfo
 ifeq ($(SUBARCH),armv7m)