[DTrace-devel] [PATCH 1/2] config: add rule to check gcc option

[Kris Van Hees]

Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
---
 Makeconfig | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/Makeconfig b/Makeconfig
index 0f7c4364..332e9519 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -163,6 +163,39 @@ $(CONFIG_H): $(objdir)/.config/config.$(1).h
 $(CONFIG_MK): $(objdir)/.config/config.$(1).mk
 endef
 
+# Generate a makefile rule to check for support for  OPTION in gcc and emit an
+# appropriate header file fragment into a file under $(objdir)/.config.
+#
+# The first argument must be suitable for a filename fragment, for a makefile
+# rule name and for a #define.
+#
+# Syntax: $(call check-gcc-option-rule,name,option)
+define check-gcc-option-rule
+$(objdir)/.config/config.$(1).h $(objdir)/.config/config.$(1).mk: $(objdir)/.config/.dir.stamp
+	case x$(HAVE_$(1)) in \
+	xyes) echo '#define HAVE_$(1) 1' > $(objdir)/.config/config.$(1).h; \
+	     echo 'HAVE_$(1)=y' > $(objdir)/.config/config.$(1).mk;; \
+	xno) echo '/* #undef HAVE_$(1) */' > $(objdir)/.config/config.$(1).h; \
+	     echo '# HAVE_$(1) undefined' > $(objdir)/.config/config.$(1).mk;; \
+	*) if $(BPFC) --help $(2) 2>&1 >/dev/null | grep error; then \
+	       echo '/* #undef HAVE_$(1) */' > $(objdir)/.config/config.$(1).h; \
+	       echo '# HAVE_$(1) undefined' > $(objdir)/.config/config.$(1).mk; \
+	   else \
+	       echo '#define HAVE_$(1) 1' > $(objdir)/.config/config.$(1).h; \
+	       echo 'HAVE_$(1)=y' > $(objdir)/.config/config.$(1).mk; \
+	   fi;; \
+	*) echo "HAVE_$(1) must be yes or no, not $(HAVE_$(1))" >&2; \
+	   false;; \
+	esac
+	rm -f $(CONFIG_H)
+	rm -f $(CONFIG_MK)
+
+$(eval $(call make-override-help,HAVE_$(1), presence of option $(2) in gcc))
+
+$(CONFIG_H): $(objdir)/.config/config.$(1).h
+$(CONFIG_MK): $(objdir)/.config/config.$(1).mk
+endef
+
 $(objdir)/.config/.dir.stamp:
 	if [[ ! -f $(objdir)/.config/.dir.stamp ]]; then \
 	    mkdir -p $(objdir)/.config; \
-- 
2.42.0