[PATCH 4/5] tools lib symbol: Add dependency test to install_headers

[Ian Rogers]

Compute the headers to be installed from their source headers and make
each have its own build target to install it. Using dependencies
avoids headers being reinstalled and getting a new timestamp which
then causes files that depend on the header to be rebuilt.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/lib/symbol/Makefile | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/tools/lib/symbol/Makefile b/tools/lib/symbol/Makefile
index ea8707b3442a..13d43c6f92b4 100644
--- a/tools/lib/symbol/Makefile
+++ b/tools/lib/symbol/Makefile
@@ -89,10 +89,10 @@ define do_install_mkdir
 endef
 
 define do_install
-	if [ ! -d '$(DESTDIR_SQ)$2' ]; then             \
-		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$2'; \
-	fi;                                             \
-	$(INSTALL) $1 $(if $3,-m $3,) '$(DESTDIR_SQ)$2'
+	if [ ! -d '$2' ]; then             \
+		$(INSTALL) -d -m 755 '$2'; \
+	fi;                                \
+	$(INSTALL) $1 $(if $3,-m $3,) '$2'
 endef
 
 install_lib: $(LIBFILE)
@@ -100,9 +100,16 @@ install_lib: $(LIBFILE)
 		$(call do_install_mkdir,$(libdir_SQ)); \
 		cp -fpR $(LIBFILE) $(DESTDIR)$(libdir_SQ)
 
-install_headers:
-	$(call QUIET_INSTALL, libsymbol_headers) \
-		$(call do_install,kallsyms.h,$(prefix)/include/symbol,644);
+HDRS := kallsyms.h
+INSTALL_HDRS_PFX := $(DESTDIR)$(prefix)/include/symbol
+INSTALL_HDRS := $(addprefix $(INSTALL_HDRS_PFX)/, $(HDRS))
+
+$(INSTALL_HDRS): $(INSTALL_HDRS_PFX)/%.h: %.h
+	$(call QUIET_INSTALL, $@) \
+		$(call do_install,$<,$(INSTALL_HDRS_PFX)/,644)
+
+install_headers: $(INSTALL_HDRS)
+	$(call QUIET_INSTALL, libsymbol_headers)
 
 install: install_lib install_headers
 
-- 
2.39.0.rc0.267.gcb52ba06e7-goog