diff --git a/build.tools/dmake.startup b/build.tools/dmake.startup
index 18bce01..9aae418 100644
--- a/build.tools/dmake.startup
+++ b/build.tools/dmake.startup
@@ -99,12 +99,12 @@ __OFLAG = -a0
 # Rules for making *$O
 # Note that $(__OFLAG) is an 'occ' thing and that the rules for pascal
 # files will not really work since '.a' is generated by compile.
-   %$O : %.c ; $(CC) $(CFLAGS) $(__OFLAG) -c $<
-   %$O : %.cc ; $(CC) $(CFLAGS) $(__OFLAG) -c $<
+   %$O : %.c ; $(CC) -o $@ $(CFLAGS) $(__OFLAG) -c $<
+   %$O : %.cc ; $(CC) -o $@ $(CFLAGS) $(__OFLAG) -c $<
 #  This is a bit of a kludge since there is no pc(1) yet.
-   %$O : %$P ; $(PC) $(PFLAGS) $< keep=$* ; $(MV) $*.a $*.o
-   %$O : %$S ; $(AS) $(ASFLAGS) $(__OFLAG) $<
-   %$O : %.asm ; $(AS) $(ASFLAGS) $(__OFLAG) $<
+   %$O : %$P ; $(PC) -o $@ $(PFLAGS) $< keep=$* ; $(MV) $*.a $*.o
+   %$O : %$S ; $(AS) -o $@ $(ASFLAGS) $(__OFLAG) $<
+   %$O : %.asm ; $(AS) -o $@ $(ASFLAGS) $(__OFLAG) $<
 #  %$O : %.cl ; class -c $<
 #  %$O : %.e %.r %.F %$F
 #       $(FC) $(RFLAGS) $(EFLAGS) $(FFLAGS) -c $<
@@ -113,13 +113,16 @@ __OFLAG = -a0
 # is repeated for them.
 # Object files ending in '.a': Force '.a' with occ
 
-   %.a : %.c ; $(CC) $(CFLAGS) $(__AFLAG) -c $<
-   %.a : %.cc ; $(CC) $(CFLAGS) $(__AFLAG) -c $<
-   %.a : %$P ; $(PC) $(PFLAGS) $< keep=$*
-   %.a : %$S ; $(AS) $(ASFLAGS) $(__AFLAG) $<
-   %.a : %.asm ; $(AS) $(ASFLAGS) $(__AFLAG) $<
+   %.a : %.c ; $(CC) -o $@ $(CFLAGS) $(__AFLAG) -c $<
+   %.a : %.cc ; $(CC) -o $@ $(CFLAGS) $(__AFLAG) -c $<
+   %.a : %$P ; $(PC) -o $@ $(PFLAGS) $< keep=$*
+   %.a : %$S ; $(AS) -o $@ $(ASFLAGS) $(__AFLAG) $<
+   %.a : %.asm ; $(AS) -o $@ $(ASFLAGS) $(__AFLAG) $<
 
 # Object files ending in '.root': Force neither '.a' nor '.o'
+# Note that since we don't specify the output file name, this set of
+# rules may not work well if the object file directory is different
+# from the source file hierarchy.
 
    %.root : %.c ; $(CC) $(CFLAGS) -c $<
    %.root : %.cc ; $(CC) $(CFLAGS) -c $<
diff --git a/build.tools/startup.mk b/build.tools/startup.mk
index 18bce01..9aae418 100644
--- a/build.tools/startup.mk
+++ b/build.tools/startup.mk
@@ -99,12 +99,12 @@ __OFLAG = -a0
 # Rules for making *$O
 # Note that $(__OFLAG) is an 'occ' thing and that the rules for pascal
 # files will not really work since '.a' is generated by compile.
-   %$O : %.c ; $(CC) $(CFLAGS) $(__OFLAG) -c $<
-   %$O : %.cc ; $(CC) $(CFLAGS) $(__OFLAG) -c $<
+   %$O : %.c ; $(CC) -o $@ $(CFLAGS) $(__OFLAG) -c $<
+   %$O : %.cc ; $(CC) -o $@ $(CFLAGS) $(__OFLAG) -c $<
 #  This is a bit of a kludge since there is no pc(1) yet.
-   %$O : %$P ; $(PC) $(PFLAGS) $< keep=$* ; $(MV) $*.a $*.o
-   %$O : %$S ; $(AS) $(ASFLAGS) $(__OFLAG) $<
-   %$O : %.asm ; $(AS) $(ASFLAGS) $(__OFLAG) $<
+   %$O : %$P ; $(PC) -o $@ $(PFLAGS) $< keep=$* ; $(MV) $*.a $*.o
+   %$O : %$S ; $(AS) -o $@ $(ASFLAGS) $(__OFLAG) $<
+   %$O : %.asm ; $(AS) -o $@ $(ASFLAGS) $(__OFLAG) $<
 #  %$O : %.cl ; class -c $<
 #  %$O : %.e %.r %.F %$F
 #       $(FC) $(RFLAGS) $(EFLAGS) $(FFLAGS) -c $<
@@ -113,13 +113,16 @@ __OFLAG = -a0
 # is repeated for them.
 # Object files ending in '.a': Force '.a' with occ
 
-   %.a : %.c ; $(CC) $(CFLAGS) $(__AFLAG) -c $<
-   %.a : %.cc ; $(CC) $(CFLAGS) $(__AFLAG) -c $<
-   %.a : %$P ; $(PC) $(PFLAGS) $< keep=$*
-   %.a : %$S ; $(AS) $(ASFLAGS) $(__AFLAG) $<
-   %.a : %.asm ; $(AS) $(ASFLAGS) $(__AFLAG) $<
+   %.a : %.c ; $(CC) -o $@ $(CFLAGS) $(__AFLAG) -c $<
+   %.a : %.cc ; $(CC) -o $@ $(CFLAGS) $(__AFLAG) -c $<
+   %.a : %$P ; $(PC) -o $@ $(PFLAGS) $< keep=$*
+   %.a : %$S ; $(AS) -o $@ $(ASFLAGS) $(__AFLAG) $<
+   %.a : %.asm ; $(AS) -o $@ $(ASFLAGS) $(__AFLAG) $<
 
 # Object files ending in '.root': Force neither '.a' nor '.o'
+# Note that since we don't specify the output file name, this set of
+# rules may not work well if the object file directory is different
+# from the source file hierarchy.
 
    %.root : %.c ; $(CC) $(CFLAGS) -c $<
    %.root : %.cc ; $(CC) $(CFLAGS) -c $<