[build] Avoid unnecessary "rm" and "touch" in dependency generation

Speed up dependency generation by omitting the totally unnecessary
"rm" and "touch" commands.  This reduces the time taken to generate
dependencies by around 6%.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

diff --git a/src/Makefile.housekeeping b/src/Makefile.housekeeping
index ad15e139c312bff06519aa00e9ca35d4bac1db22..2b244e22dc53b7b8a4349f30ccb5b32451bc1467 100644 (file)
--- a/src/Makefile.housekeeping
+++ b/src/Makefile.housekeeping
@@ -466,11 +466,9 @@ define src_template
 
        @$(ECHO) "  [DEPS] $(1)"
        @$(MKDIR) -p $(dir $(2))
-       @$(RM) $(2)
-       @$(TOUCH) $(2)
        @$(CPP) $(CFLAGS) $(CFLAGS_$(3)) $(CFLAGS_$(4)) -DOBJECT=$(4) \
                -Wno-error -M $(1) -MG -MP | \
-               sed 's/\.o\s*:/_DEPS =/' >> $(2)
+               sed 's/\.o\s*:/_DEPS =/' > $(2)
        @$(ECHO_E) '\n$$(BIN)/$(4).o :' \
                 '$(1) $$(MAKEDEPS) $$(POST_O_DEPS) $$($(4)_DEPS)' \
                 '\n\t$$(QM)$(ECHO) "  [BUILD] $$@"' \
@@ -815,8 +813,6 @@ define media_template
 
        @$(ECHO) "  [MEDIADEPS] $(1)"
        @$(MKDIR) -p $(dir $(2))
-       @$(RM) $(2)
-       @$(TOUCH) $(2)
        @$(ECHO_E) '$$(BIN)/%.$(1) : $$(BIN)/%.$(1).zbin' \
                  '\n\t$$(QM)$(ECHO) "  [FINISH] $$@"' \
                  '\n\t$$(Q)$$(CP) $$< $$@' \