Avoid overwriting of already set DOS_DEPS_OS and DYNLIBS_DEPS_OS variables for linux RTL

rtl/linux/Makefile

@@ -3247,8 +3247,6 @@ SYSINCDEPS=$(addprefix $(INC)/,$(SYSINCNAMES))
 include $(PROCINC)/makefile.cpu
 SYSCPUDEPS=$(addprefix $(PROCINC)/,$(CPUINCNAMES))
 SYSDEPS=$(SYSINCDEPS) $(SYSCPUDEPS)
-DOS_DEPS_OS=$(UNIXUNIT)$(PPUEXT)
-DYNLIBS_DEPS_OS=$(DLUNIT)$(PPUEXT) 
 SYSNRINC=$(ARCH)/sysnr.inc
 ifneq ($(findstring -Cg ,$(COMPILER)),)
   PIC_OPT=1

rtl/linux/Makefile.fpc

@@ -175,9 +175,6 @@ SYSCPUDEPS=$(addprefix $(PROCINC)/,$(CPUINCNAMES))
 # Put $(SYSTEMUNIT) unit dependencies together.
 SYSDEPS=$(SYSINCDEPS) $(SYSCPUDEPS)
 
-DOS_DEPS_OS=$(UNIXUNIT)$(PPUEXT)
-DYNLIBS_DEPS_OS=$(DLUNIT)$(PPUEXT) 
-
 SYSNRINC=$(ARCH)/sysnr.inc
 
 # Set PIC_OPT to 1 if -Cg or -fPIC is used