Use compiler flags for header dependency file generation when possible.

configure/CONFIG.gnuCommon

@@ -53,3 +53,5 @@ LOADABLE_SHRLIB_LDFLAGS = -shared -fPIC
 
 GNU_LDLIBS_YES = -lgcc
 
+# Use GNU compiler flags to generate header dependancies files
+HDEPENDS_METHOD = CFLAGS

configure/os/CONFIG.darwinCommon.darwinCommon

@@ -106,6 +106,15 @@ vpath %.m $(USR_VPATH) $(ALL_SRC_DIRS)
 %.o: %.m
 	$(COMPILE.c) -c $<
 
+#
+# Header dependency file generation
+#
+# Use GNU compiler flags when ARCH_CLASS is a single arch value
+# otherwise use perl script command
+SINGLE_ARCH=$(filter 1,$(words $(ARCH_CLASS)))
+HDEPENDS_CFLAGS = $(if $(SINGLE_ARCH),$(HDEPENDS_CFLAGS_$(HDEPENDS)))
+HDEPENDS_METHOD = $(if $(SINGLE_ARCH),CFLAGS,CMD)
+
 #--------------------------------------------------
 # Allow site overrides
 -include $(CONFIG)/os/CONFIG_SITE.darwinCommon.darwinCommon

configure/os/CONFIG.solarisCommon.solarisCommon

@@ -58,6 +58,10 @@ OP_SYS_LDFLAGS += -z ignore -z combreloc -z lazyload
 #COMPILE_FILTER.c = 2>&1 | $(EPICS_BASE)/configure/tools/filterWarnings.pl
 #COMPILE_FILTER.cpp = $(COMPILE_FILTER.c)
 
+# Header dependency file generation command
+HDEPENDS_METHOD=CMD 
+HDEPENDSCMD = $(if $(filter .c,$(suffix $<)),$(COMPILE.c),$(COMPILE.cpp)) -xM1 $< >$*$(DEP)
+
 #--------------------------------------------------
 # Allow site overrides
 -include $(CONFIG)/os/CONFIG_SITE.solarisCommon.solarisCommon