build: Avoid excessive dep generation on Makefile changes.

Letting error2 depend on config.h instead of Makefile should be no
worse, and it does not cause all dependencies to be recreated in the
common case where config.h remains unchanged after reconfiguration.

diff --git a/Makefile.real b/Makefile.real
index 978bebfa9dc82e62a4eff2828d40a710915b1d4b..58761a7bf24e1121894920d65e18b2bcca65fd88 100644 (file)
--- a/Makefile.real
+++ b/Makefile.real
@@ -167,7 +167,7 @@ $(man_dir)/para_%.1: $(ggo_dir)/%.ggo man_util.bash | $(man_dir) $(help2man_dir)
 $(hostbin_dir)/error2: error2.c | $(hostbin_dir)
        @[ -z "$(Q)" ] || echo 'HCC $<'
        $(Q) $(HOSTCC) -o $@ $<
-error2.h: $(hostbin_dir)/error2 Makefile
+error2.h: $(hostbin_dir)/error2 config.h
        @[ -z "$(Q)" ] || echo 'ER2 $<'
        @echo "$(object_executable_matrix)" | $< > $@