ChangeLogTag:Wed Jan 7 23:06:57 UTC 2004 Don Hinton <dhinton@dre.vanderbilt.edu>

8 files changed, 156 insertions, 364 deletions

diff --git a/include/makeinclude/all_in_one.GNU b/include/makeinclude/all_in_one.GNU
index cf0da1f537a..ceb3890b30d 100644
--- a/include/makeinclude/all_in_one.GNU
+++ b/include/makeinclude/all_in_one.GNU
@@ -11,9 +11,7 @@ ALL_IN_ONE_GNU = 1
 # Include wrapper macros to all user defines, etc.
 include $(ACE_ROOT)/include/makeinclude/wrapper_macros.GNU
 
-ifndef TAO_ROOT
-  TAO_ROOT = $(ACE_ROOT)/TAO
-endif
+TAO_ROOT ?= $(ACE_ROOT)/TAO
 
 ifneq ($(ADDITIONAL_INCLUDE),)
   include $(ADDITIONAL_INCLUDE)
@@ -29,22 +27,16 @@ include $(ACE_ROOT)/include/makeinclude/component_check.GNU
 # If no required components are missing, set the real targets
 ifeq ($(MISSING_COMPONENTS),)
   ifdef BIN_UNCHECKED
-    ifndef BIN
-      BIN = $(BIN_UNCHECKED)
-    endif # !BIN
+    BIN += $(BIN_UNCHECKED)
   endif # !BIN_UNCHECKED
   ifdef static_libs
     ifdef LIB_UNCHECKED
-      ifndef LIB
-        LIB = $(LIB_UNCHECKED)
-      endif # !LIB
+      LIB += $(LIB_UNCHECKED)
     endif # !LIB_UNCHECKED
   endif # static_libs
   ifdef shared_libs
     ifdef SHLIB_UNCHECKED
-      ifndef SHLIB
-        SHLIB = $(SHLIB_UNCHECKED)
-      endif # !SHLIB
+      SHLIB += $(SHLIB_UNCHECKED)
     endif # !SHLIB_UNCHECKED
   endif # !shared_libs
 endif # COMPILE_COMPONENT
@@ -76,9 +68,7 @@ endif # BIN
 include $(ACE_ROOT)/include/makeinclude/rules.local.GNU
 
 # Remove the -g option if requested.
-ifndef SUPPRESS_DASH_G
-  SUPPRESS_DASH_G ?=
-endif
+SUPPRESS_DASH_G ?=
 ifeq ($(SUPPRESS_DASH_G),1)
   DCFLAGS := $(filter-out -g, $DCFLAGS)
 endif
diff --git a/include/makeinclude/platform_g++_common.GNU b/include/makeinclude/platform_g++_common.GNU
index 047c8d6e158..065f7c4c8c5 100644
--- a/include/makeinclude/platform_g++_common.GNU
+++ b/include/makeinclude/platform_g++_common.GNU
@@ -1,3 +1,4 @@
+# -*- Makefile -*-
 # $Id$
 #
 # Common file help turn on/off explicit template instantiation
@@ -46,12 +47,8 @@ endif
 # The correct flags to pass to the linker for ELF dynamic shared library
 # versioning. None of this works on OpenBSD's ld.
 # If the platform file didn't already set versioned_so, default to 1.
-ifndef versioned_so
-  versioned_so = 1
-endif
-ifndef with_ld
-  with_ld ?=
-endif
+versioned_so ?= 1
+with_ld ?=
 ifeq ($(versioned_so),1)
   ifeq ($(with_ld),hpux)
     SOFLAGS += -Wl,+h -Wl,$(SONAME)
@@ -67,36 +64,34 @@ ifeq ($(versioned_so),1)
   endif
 endif
 
-ifndef static_libs_only
-  static_libs_only ?=
-endif
+static_libs_only ?=
+
+# Only modify LDFLAGS if DLD has been set.
+ifneq ($(DLD),)
+  ifeq ($(DLD),$(CXX_FOR_VERSION_TEST)) # only try this is we are using ld through gcc
+    LD_FOR_VERSION_TEST = $(shell $(CXX_FOR_VERSION_TEST) -print-prog-name=ld)
+  else
+    LD_FOR_VERSION_TEST = $(DLD)
+  endif # DLD = CXX_FOR_VERSION_TEST
+  # The -E option is GNU ld specific 
+  GNU_LD := $(shell sh -c '$(LD_FOR_VERSION_TEST) -v 2>&1 | grep -c "GNU ld"')
+endif # DLD
+
+STATIC_LINK_FLAG ?=
+ifeq ($(GNU_LD),1)
+  STATIC_LINK_FLAG = -static
+endif # GNU_LD
 
 # Add all symbols to the dynamic symbol table.  Needed to enable dynamic_cast
 # for shared libraries. (see http://gcc.gnu.org/faq.html#dso)
 ifeq ($(shared_libs), 1)
   ifneq ($(static_libs_only), 1)
-
-    # Only modify LDFLAGS if DLD has been set.
-    ifneq ($(DLD),)
-      ifeq ($(DLD),$(CXX_FOR_VERSION_TEST)) # only try this is we are using ld through gcc
-        LD_FOR_VERSION_TEST = $(shell $(CXX_FOR_VERSION_TEST) -print-prog-name=ld)
-      else
-        LD_FOR_VERSION_TEST = $(DLD)
-      endif # DLD = CXX_FOR_VERSION_TEST
-
-      # The -E option is GNU ld specific 
-      GNU_LD := $(shell sh -c '$(LD_FOR_VERSION_TEST) -v 2>&1 | grep -c "GNU ld"')
-      ifeq ($(GNU_LD),1)
-
-        # Make sure this version of ld supports the -E option.
-        LD_EXPORT_DEFINED := $(shell sh -c '$(LD_FOR_VERSION_TEST) -E 2>&1 | grep -i -e "(option|flag)" /dev/null; echo $$?')
-        ifeq ($(LD_EXPORT_DEFINED),1)
-          LDFLAGS += -Wl,-E
-        endif # LD_EXPORT_DEFINED = 1
-
-      endif # GNU ld
-
-    endif # DLD
-
+    ifeq ($(GNU_LD),1)
+      # Make sure this version of ld supports the -E option.
+      LD_EXPORT_DEFINED := $(shell sh -c '$(LD_FOR_VERSION_TEST) -E 2>&1 | grep -i -e "(option|flag)" /dev/null; echo $$?')
+      ifeq ($(LD_EXPORT_DEFINED),1)
+        LDFLAGS += -Wl,-E
+      endif # LD_EXPORT_DEFINED = 1
+    endif # GNU ld
   endif # static_libs_only
 endif # shared_libs
diff --git a/include/makeinclude/platform_linux.GNU b/include/makeinclude/platform_linux.GNU
index 94b81d6527a..ea7c8737640 100644
--- a/include/makeinclude/platform_linux.GNU
+++ b/include/makeinclude/platform_linux.GNU
@@ -1,3 +1,4 @@
+# -*- Makefile -*-
 # $Id$
 
 # According to Bryon G. Rigg <bgrigg@opus.bcbnet.com>, this file
@@ -7,13 +8,10 @@
 # optimize = 1
 
 # We always include config-linux.h on Linux platforms.
-ifndef ACE_PLATFORM_CONFIG
-  ACE_PLATFORM_CONFIG = config-linux.h
-endif
+ACE_PLATFORM_CONFIG ?= config-linux.h
+
+exceptions ?= 1
 
-ifndef exceptions
-  exceptions = 1
-endif
 ifeq (,$(debug))
   debug = 1
 endif
@@ -21,9 +19,7 @@ ifeq (,$(optimize))
   optimize = 1
 endif
 
-ifndef threads
-  threads = 1
-endif
+threads ?= 1
 
 PLATFORM_XT_CPPFLAGS=
 PLATFORM_XT_LIBS=-lXt
@@ -52,10 +48,7 @@ PLATFORM_WX_LDFLAGS =
 PLATFORM_AIO_SUPPORT := \
        $(shell test -e /usr/lib/librt.so && echo -DACE_HAS_AIO_CALLS)
 
-ifndef ssl
-  ssl = 0
-endif
-
+ssl ?= 0
 ifeq ($(ssl),1)
   # Some Linux OpenSSL installations compile in Kerberos support.  Add
   # the Kerberos include path to preprocessor include path.
@@ -69,16 +62,13 @@ ifeq ($(ssl),1)
   PLATFORM_SSL_CPPFLAGS += -I/usr/kerberos/include
 endif # ssl
 
-ifndef insure
-  insure = 0
-endif
-
+insure ?= 0
 ifeq ($(insure),1)
-CC  = insure
-CXX = insure
+  CC  = insure
+  CXX = insure
 else
-CC  = gcc
-CXX = g++
+  CC  = gcc
+  CXX = g++
 endif
 
 CFLAGS  += -W -Wall -Wpointer-arith -pipe
@@ -133,9 +123,7 @@ ifeq ($(threads),1)
     endif # ! PRELIB
 endif
 
-ifndef sctp
-  sctp ?=
-endif
+sctp ?=
 # support for OpenSS7 SCTP
 ifeq ($(sctp),openss7)
   PLATFORM_SCTP_CPPFLAGS= -DACE_HAS_OPENSS7_SCTP
diff --git a/include/makeinclude/rules.bin.GNU b/include/makeinclude/rules.bin.GNU
index 0f45b83db8c..73ffefb9245 100644
--- a/include/makeinclude/rules.bin.GNU
+++ b/include/makeinclude/rules.bin.GNU
@@ -30,12 +30,12 @@ PSRC += $(addsuffix .cpp, $(CLEANUP_BIN))
 
 CLEANUP_INSTALL += $(CLEANUP_BIN:%=$(INSBIN)/%$(VAR)$(EXEEXT))
 
-ifndef CHORUSLINK
-  CHORUSLINK ?=
-endif # CHORUSLINK
-ifndef using_aix_vacpp
-  using_aix_vacpp ?=
-endif
+CHORUSLINK ?=
+using_aix_vacpp ?=
+
+ifeq ($(static_libs_only),1)
+  LDFLAGS += $(STATIC_LINK_FLAG)
+endif # static_libs_only=1
 
 ifeq ($(CHORUSLINK),true)
 $(BIN): %: $(VDIR)%.$(OBJEXT) $(VOBJS)
diff --git a/include/makeinclude/rules.lib.GNU b/include/makeinclude/rules.lib.GNU
index fdf6bcce485..be70a002159 100644
--- a/include/makeinclude/rules.lib.GNU
+++ b/include/makeinclude/rules.lib.GNU
@@ -35,28 +35,23 @@ endif # versioned_so
 # The following targets arrange to build both unshared and shared libraries
 #----------------------------------------------------------------------------
 
-ifndef LIB
-  LIB ?=
-endif
+LIB ?=
 VLIB = $(LIB:%.$(LIBEXT)=%$(VAR).$(LIBEXT))
+CLEANUP_VLIB = $(CLEANUP_LIB:%.$(LIBEXT)=%$(VAR).$(LIBEXT))
 
 # Add VLIB to VLIBS if building static_libs.
 ifdef static_libs 
   VLIBS += $(VLIB)
 endif
 
-ifndef SHLIB
-  SHLIB ?=
-endif
+SHLIB ?=
 # Setup shared library variables, including versions.
 VSHLIB_NO_VER = $(SHLIB:%.$(SOEXT)=%$(VAR).$(SOEXT))
 CLEANUP_VSHLIB_NO_VER = $(CLEANUP_SHLIB:%.$(SOEXT)=%$(VAR).$(SOEXT))
 VSHLIB = $(VSHLIB_NO_VER:%=%$(SOVERSION))
 CLEANUP_VSHLIB = $(CLEANUP_VSHLIB_NO_VER:%=%$(SOVERSION))
 
-ifndef SHLIBA
-  SHLIBA ?=
-endif
+SHLIBA ?=
 VSHLIBA = $(SHLIBA:%.$(LIBEXT)=%$(VAR).$(LIBEXT))
 
 # Add VSHLIB if we're building shared_libs.
@@ -76,6 +71,12 @@ ifeq ($(VLIBS),)
   ifeq ($(LIB_WARNING),1)
     @echo Warning: rules.lib.GNU included, but no library targets detected.
   endif # LIB_WARNING
+else # VLIBS
+  # Libraries always depend on idl_stubs, if they exist.
+  IDL_SRC ?=
+  ifeq ($(IDL_SRC),)
+    $(VLIBS): $(IDL_SRC)
+  endif # IDL_SRC
 endif # !VLIBS
 
 VLOBJS   += $(addsuffix .$(OBJEXT),$(addprefix $(VDIR),$(basename $(notdir $(LSRC)))))
@@ -88,7 +89,7 @@ VSHOBJS1 = $(addsuffix .$(OBJEXT),$(addprefix $(VSHDIR),$(basename $(notdir $(LS
 
 ifdef static_libs
   LIB_INSTALL += $(VLIB:%=$(INSLIB)/%)
-  CLEANUP_INSTALL += $(CLEANUP_LIB:%=$(INSLIB)/%)
+  CLEANUP_INSTALL += $(CLEANUP_VLIB:%=$(INSLIB)/%)
 endif # static_libs
 
 ifdef shared_libs
@@ -101,13 +102,8 @@ ifdef shared_libs
   endif
 endif # shared_libs
 
-
-ifndef ace_lib_prelink
-  ace_lib_prelink = 0
-endif
-ifndef aix_build
-  aix_build = 0
-endif
+ace_lib_prelink ?= 0
+aix_build ?= 0
 
 $(VLIB): $(VLOBJS)
 
diff --git a/include/makeinclude/rules.local.GNU b/include/makeinclude/rules.local.GNU
index 99fff4f8dd6..f4198157511 100644
--- a/include/makeinclude/rules.local.GNU
+++ b/include/makeinclude/rules.local.GNU
@@ -50,23 +50,12 @@ all.local: makefile_name.local $(split_target) build.objdirs build.local install
 #----------------------------------------------------------------------------
 
 
-ifndef IDL_SRC
-  IDL_SRC ?=
-endif
-ifndef VLIBS
-  VLIBS ?=
-endif
-ifndef BUILD
-  BUILD ?=
-endif
-ifndef VBIN
-  ifdef BIN
-    VBIN = $(BIN:%=%$(VAR))
-    $(VBIN): $(VLIBS)
-  else
-    VBIN ?=
-  endif
-endif
+IDL_SRC ?=
+VLIBS ?=
+BUILD ?=
+BIN ?=
+VBIN ?= $(BIN:%=%$(VAR))
+$(VBIN): $(VLIBS)
 
 # Always build the V* targets in this order.  We control assignment to them
 # elsewhere. We add the existing $(BUILD) targets to the end to allow the
@@ -82,9 +71,7 @@ build.local: $(VBUILD)
 
 # C++ related targets
 
-ifndef OS
-  OS ?=
-endif
+OS ?=
 ifeq ($(OS),"Windows_NT")
 $(VDIR)%.obj: %.c
 	$(COMPILE.c) $(CC_OUTPUT_FLAG) $@ $<
@@ -207,20 +194,15 @@ show_uninit:
 #       Installation targets
 #----------------------------------------------------------------------------
 
-ifndef INSTALL
-  INSTALL ?=
-endif # INSTALL
-# Libraries always depend on idl_stubs, if they exist.
-ifdef IDL_SRC
-  $(VLIBS): $(IDL_SRC)
-endif
-
+INSTALL ?=
 # Always add LIB_INSTALL to INSTALL, so libs will get installed even no BIN
 # is built.  LIB_INSTALL is a dependency for BIN, so libs are installed prior
-# to use.  Also, make LIB_INSTALL depend on VLIB, so libs get built prior to
+# to use.  Also, make LIB_INSTALL depend on VLIBS, so libs get built prior to
 # installation.
-INSTALL += $(LIB_INSTALL)
-$(LIB_INSTALL): $(VLIBS)
+ifdef LIB_INSTALL
+  INSTALL += $(LIB_INSTALL)
+  $(LIB_INSTALL): $(VLIBS)
+endif
 
 install.local: $(INSTALL)
 
@@ -347,23 +329,14 @@ endif # DO_CLEANUP
 #       Dependency generation target
 #----------------------------------------------------------------------------
 
-ifndef MAKEFILE
-  MAKEFILE = Makefile
-endif # ! MAKEFILE
-
-ifndef DEPENDENCY_FILE
-  DEPENDENCY_FILE = $(MAKEFILE)
-endif
+MAKEFILE ?= Makefile
+DEPENDENCY_FILE ?= $(MAKEFILE)
 
-ifndef TAO_ROOT
-  TAO_ROOT = $(ACE_ROOT)/TAO
-endif # TAO_ROOT
+TAO_ROOT ?= $(ACE_ROOT)/TAO
 
 # If no libraries are build in the current directory (actually, if
 # rules.lib.GNU isn't included), then SOEXT might not be set.
-ifndef SOEXT
-  SOEXT=so
-endif # SOEXT
+SOEXT ?= so
 
 ORIGdepend.local: $(MAKEFILE)
 	@$(RM) $(MAKEFILE).old
@@ -415,12 +388,9 @@ depend.local: $(MAKEFILE) idl_stubs.local
 #       RCS info target
 #----------------------------------------------------------------------------
 
-ifndef IDL_FILES
-  IDL_FILES ?=
-endif
-ifndef IDL_CLIENT_HDR_EXT
-  IDL_CLIENT_HDR_EXT ?=
-endif
+IDL_FILES ?=
+IDL_CLIENT_HDR_EXT ?=
+
 idl_stubs.local: $(foreach file, $(IDL_FILES), $(file)$(IDL_CLIENT_HDR_EXT))
 
 ifdef $(TAO_IDL_DEP)
diff --git a/include/makeinclude/rules.nested.GNU b/include/makeinclude/rules.nested.GNU
index ac864a595c0..169a02acdfb 100644
--- a/include/makeinclude/rules.nested.GNU
+++ b/include/makeinclude/rules.nested.GNU
@@ -10,27 +10,13 @@
 # variable must be set to its actual name before including this
 # file to allow the recursive MAKE to work properly.
 
-ifndef MAKEFILE
-  MAKEFILE ?=
-endif
-ifeq ($(MAKEFILE),)
-  MAKEFILE = Makefile
-endif # ! MAKEFILE
-
-ifndef SUBDIR_MAKEFILE
-  SUBDIR_MAKEFILE ?=
-endif
-ifeq ($(SUBDIR_MAKEFILE),)
-  SUBDIR_MAKEFILE=$(MAKEFILE)
-endif
+MAKEFILE ?= Makefile
+SUBDIR_MAKEFILE ?= $(MAKEFILE)
 
 # Make sure that we build directories with DIRS= in sequence instead of in
 # parallel, unless DIRS_PARALLEL is set, in which case they may be built
 # in parallel if enabled by the proper flags and not disabled elsewhere.
-
-ifndef DIRS_PARALLEL
-  DIRS_PARALLEL ?=
-endif # DIRS_PARALLEL
+DIRS_PARALLEL ?=
 
 ifeq ($(DIRS_PARALLEL),)
 .NOTPARALLEL:
diff --git a/include/makeinclude/wrapper_macros.GNU b/include/makeinclude/wrapper_macros.GNU
index 647d2be0820..22948a703a6 100644
--- a/include/makeinclude/wrapper_macros.GNU
+++ b/include/makeinclude/wrapper_macros.GNU
@@ -257,36 +257,24 @@ ACE_MAJOR_VERSION := $(shell awk '/ACE_MAJOR_VERSION/ { print $$3}' ${ACE_ROOT}/
 ACE_MINOR_VERSION := $(shell awk '/ACE_MINOR_VERSION/ { print $$3}' ${ACE_ROOT}/ace/Version.h)
 ACE_BETA_VERSION := $(shell awk '/ACE_BETA_VERSION/ { print $$3}' ${ACE_ROOT}/ace/Version.h)
 
-ifndef PACE_ROOT
-  PACE_ROOT = $(ACE_ROOT)/PACE
-endif # PACE_ROOT
+PACE_ROOT ?= $(ACE_ROOT)/PACE
 
 # Define some variables to silence warnings
-ifndef SHR_FILTER
-  SHR_FILTER ?=
-endif # SHR_FILTER
+SHR_FILTER ?=
 
 # Include this before the below variables to make it possible for
 # platform_macros.GNU to set default values for them.
 include $(ACE_ROOT)/include/makeinclude/platform_macros.GNU
 
 # Define some variables to silence warnings
-ifndef GHS
-  GHS ?=
-endif
-ifndef CHORUS
-  CHORUS ?=
-endif
-ifndef AIX_TEMPLATE_HACK
-  AIX_TEMPLATE_HACK ?=
-endif
+GHS ?=
+CHORUS ?=
+AIX_TEMPLATE_HACK ?=
 
 # $(ACE_PLATFORM_CONFIG) is used in dependency rules and corresponds to the
 # platform dependent config-*.h file included in config.h, and can be set
 # in your platform_*.GNU file or platform_macros.GNU.
-ifndef ACE_PLATFORM_CONFIG
-  ACE_PLATFORM_CONFIG = config.h
-endif
+ACE_PLATFORM_CONFIG ?= config.h
 
 ifeq ($(threads),0)
   ifneq ($(findstring -DACE_MT_SAFE=0,$(CPPFLAGS)),-DACE_MT_SAFE=0)
@@ -298,95 +286,54 @@ endif # threads
 #### Defaults are exceptions off (0), fast off (0), rtti off (0), and
 #### versioned_so on (1).
 ####
-ifndef exceptions
-  exceptions = 0
-endif
+exceptions ?= 0
 
-ifndef fast
-  fast = 0
-endif
+fast ?= 0
 
 # @@@ Should this really be the default?  Or should we let the
 # compiler choose?
-ifndef rtti
-  rtti = 0
-endif
+rtti ?= 0
 
 ifeq (,$(versioned_so))
   versioned_so = 1
 endif
-ifndef SOVERSION
-  SOVERSION ?=
-endif # SOVERSION
-ifndef SONAME
-  SONAME ?=
-endif
+SOVERSION ?=
+SONAME ?=
 
 #----------------------------------------------------------------------------
 #      Platform-independent macro definitions
 #----------------------------------------------------------------------------
 
-ifndef INCLDIRS
-  INCLDIRS ?=
-endif
-ifndef DEFFLAGS
-  DEFFLAGS ?=
-endif
+INCLDIRS ?=
+DEFFLAGS ?=
 
 CPPFLAGS        += $(DEFFLAGS) $(INCLDIRS)
 
 # Define default extentions for IDL-generated files
-ifndef IDL_CLIENT_HDR_EXT
-IDL_CLIENT_HDR_EXT = C.h
-endif
-ifndef IDL_CLIENT_INL_EXT
-IDL_CLIENT_INL_EXT = C.i
-endif
-ifndef IDL_CLIENT_SRC_EXT
-IDL_CLIENT_SRC_EXT = C.cpp
-endif
-ifndef IDL_SERVER_HDR_EXT
-IDL_SERVER_HDR_EXT = S.h
-endif
-ifndef IDL_SERVER_INL_EXT
-IDL_SERVER_INL_EXT = S.i
-endif
-ifndef IDL_SERVER_SRC_EXT
-IDL_SERVER_SRC_EXT = S.cpp
-endif
-ifndef IDL_SERVER_THDR_EXT
-IDL_SERVER_THDR_EXT = S_T.h
-endif
-ifndef IDL_SERVER_TINL_EXT
-IDL_SERVER_TINL_EXT = S_T.i
-endif
-ifndef IDL_SERVER_TSRC_EXT
-IDL_SERVER_TSRC_EXT = S_T.cpp
-endif
+IDL_CLIENT_HDR_EXT ?= C.h
+IDL_CLIENT_INL_EXT ?= C.i
+IDL_CLIENT_SRC_EXT ?= C.cpp
+IDL_SERVER_HDR_EXT ?= S.h
+IDL_SERVER_INL_EXT ?= S.i
+IDL_SERVER_SRC_EXT ?= S.cpp
+IDL_SERVER_THDR_EXT ?= S_T.h
+IDL_SERVER_TINL_EXT ?= S_T.i
+IDL_SERVER_TSRC_EXT ?= S_T.cpp
 
 ifeq (,$(findstring -I$(ACE_ROOT),$(INCLDIRS)))
   INCLDIRS        += -I$(ACE_ROOT)
 endif
-ifndef INSBIN
-  INSBIN          = $(ACE_ROOT)/bin
-endif
-ifndef INSINC
-  INSINC          = $(ACE_ROOT)/ace
-endif
-ifndef INSLIB
-  INSLIB          = $(ACE_ROOT)/ace
-endif
-ifndef INSMAN
-  INSMAN          = $(ACE_ROOT)/man
-endif
+INSBIN          ?= $(ACE_ROOT)/bin
+INSINC          ?= $(ACE_ROOT)/ace
+INSLIB          ?= $(ACE_ROOT)/ace
+INSMAN          ?= $(ACE_ROOT)/man
+
 ifeq (,$(findstring -L$(ACE_ROOT)/ace,$(LDFLAGS)))
   LDFLAGS         += -L$(ACE_ROOT)/ace -L./
 endif
-LEX             = flex
+LEX             ?= flex
 
-ifndef EXEEXT
-  EXEEXT ?=
-endif
+EXEEXT ?=
 
 ifndef COMSPEC
   ifdef ComSpec
@@ -409,20 +356,14 @@ PCCFLAGS        += #### set in platform_macros.GNU file, e.g., -p
 VAR             =
 
 # Let users override the default VDIR directories
-ifndef VDIR
-VDIR            = .obj/
-endif # VDIR
-ifndef VSHDIR
-  VSHDIR        = .shobj/
-endif # VSHDIR
-
-ifndef ACELIB
-  ACELIB = -lACE
-endif
+VDIR          ?= .obj/
+VSHDIR        ?= .shobj/
+
+ACELIB ?= -lACE
 
 # NOTE: VLDLIBS is defined below, in case it is overridden for static-
 #       or shared-only builds.
-YACC            = bison
+YACC          ?= bison
 
 
 
@@ -439,29 +380,13 @@ ifeq ($(findstring g++,$(CXX)),g++)
   endif # ! ACE_HAS_GNUG_PRE_2_8
 endif # g++
 
-ifndef OBJEXT
-  OBJEXT=o
-endif
-
-ifndef SOEXT
-  SOEXT=so
-endif
-
-ifndef LIBEXT
-  LIBEXT=a
-endif
-
-ifndef CC_OUTPUT_FLAG
-  CC_OUTPUT_FLAG = -o
-endif # CC_OUTPUT_FLAG
+OBJEXT ?= o
+SOEXT ?= so
+LIBEXT ?= a
 
-ifndef SO_OUTPUT_FLAG
-  SO_OUTPUT_FLAG = -o
-endif # SO_OUTPUT_FLAG
-
-ifndef LINK_OUTPUT_FLAG
-  LINK_OUTPUT_FLAG = -o
-endif # LINK_OUTPUT_FLAG
+CC_OUTPUT_FLAG ?= -o
+SO_OUTPUT_FLAG ?= -o
+LINK_OUTPUT_FLAG ?= -o
 
 #----------------------------------------------------------------------------
 #      make flags
@@ -476,9 +401,7 @@ ifneq ($(optimize),)
   CCFLAGS += $(OCCFLAGS)
 endif # optimize
 
-ifndef split
-  split = 0
-endif
+split ?= 0
 ifeq ($(split),0)
   override split =
 endif # split
@@ -522,9 +445,7 @@ ifneq ($(xt_reactor),)
   ACE_MAKE_OPTIONS += xt_reactor
 endif # xt_reactor
 
-ifndef fl_reactor
-  fl_reactor ?=
-endif
+fl_reactor ?=
 ifeq ($(fl_reactor),0)
   override fl_reactor =
 endif # fl_reactor
@@ -538,9 +459,7 @@ ifneq ($(fl_reactor),)
   ACE_MAKE_OPTIONS += rl_reactor
 endif # fl_reactor
 
-ifndef tk_reactor
-  tk_reactor ?=
-endif
+tk_reactor ?=
 ifeq ($(tk_reactor),0)
   override tk_reactor =
 endif # tk_reactor
@@ -553,9 +472,7 @@ ifneq ($(tk_reactor),)
   ACE_MAKE_OPTIONS += tk_reactor
 endif # tk_reactor
 
-ifndef qt_reactor
-  qt_reactor ?=
-endif
+qt_reactor ?=
 ifeq ($(qt_reactor),0)
   override qt_reactor =
 endif # qt_reactor
@@ -568,18 +485,14 @@ ifneq ($(qt_reactor),)
   ACE_MAKE_OPTIONS += qt_reactor
 endif # qt_reactor
 
-ifndef QTDIR
-  QTDIR ?=
-endif
+QTDIR ?=
 ifneq ($(QTDIR),)
   MOC = ${QTDIR}/bin/moc
 else
   MOC = moc
 endif
 
-ifndef gtk_reactor
-  gtk_reactor ?=
-endif
+gtk_reactor ?=
 ifeq ($(gtk_reactor),0)
   override gtk_reactor =
 endif # gtk_reactor
@@ -592,9 +505,7 @@ ifneq ($(gtk_reactor),)
   ACE_MAKE_OPTIONS += gtk_reactor
 endif # gtk_reactor
 
-ifndef rapi
-  rapi ?=
-endif
+rapi ?=
 ifeq ($(rapi),0)
      override rapi =
 endif #rapi
@@ -606,9 +517,7 @@ ifneq ($(rapi),)
   ACE_MAKE_OPTIONS += rapi
 endif # rapi
 
-ifdef sctp
-  sctp ?=
-endif
+sctp ?=
 ifeq ($(sctp),0)
      override sctp =
 endif #rapi
@@ -621,9 +530,7 @@ ifneq ($(sctp),)
   ACE_MAKE_OPTIONS += sctp
 endif
 
-ifndef ace_with_gl
-  ace_with_gl ?=
-endif
+ace_with_gl ?=
 ifeq ($(ace_with_gl),0)
   override ace_with_gl =
 endif # ace_with_gl
@@ -636,9 +543,7 @@ ifneq ($(ace_with_gl),)
   ACE_MAKE_OPTIONS += ace_with_gl
 endif # ace_with_gl
 
-ifndef ace_with_xll
-  ace_with_x11 ?=
-endif
+ace_with_x11 ?=
 ifeq ($(ace_with_x11),0)
   override ace_with_x11 =
 endif # ace_with_x11
@@ -650,9 +555,7 @@ ifneq ($(ace_with_x11),)
   ACE_MAKE_OPTIONS += ace_with_x11
 endif # ace_with_x11
 
-ifndef ssl
-  ssl ?=
-endif
+ssl ?=
 ifeq ($(ssl),0)
   override ssl =
 else
@@ -690,9 +593,7 @@ else  # exceptions
   ACE_MAKE_OPTIONS += exceptions
 endif # exceptions
 
-ifndef profile
-  profile ?=
-endif
+profile ?=
 ifeq ($(profile),0)
   override profile =
 endif # profile
@@ -718,16 +619,12 @@ ifeq ($(static_libs),0)
   override static_libs =
 endif # static_libs
 
-ifndef shared_libs_only
-  shared_libs_only ?=
-endif
+shared_libs_only ?=
 ifeq ($(shared_libs_only),0)
   override shared_libs_only =
 endif # shared_libs_only
 
-ifndef static_libs_only
-  static_libs_only ?=
-endif
+static_libs_only ?=
 ifeq ($(static_libs_only),0)
   override static_libs_only =
 endif # static_libs_only
@@ -755,9 +652,7 @@ ifdef static_libs
   ACE_MAKE_OPTIONS += static_libs
 endif
 
-ifndef ACE_SHLIBS
-  ACE_SHLIBS ?=
-endif # ACE_SHLIBS
+ACE_SHLIBS ?=
 
 ifdef shared_libs
   ifdef SHLIBA
@@ -784,9 +679,7 @@ endif # kylix
 
 VLDLIBS = $(LDLIBS) $(ACELIB) $(LIBS)
 
-ifndef probe
-  probe ?=
-endif
+probe ?=
 ifeq ($(probe),0)
   override probe =
 endif # probe
@@ -795,9 +688,7 @@ ifeq ($(probe),1)
     CPPFLAGS += -DACE_COMPILE_TIMEPROBES
 endif # probe
 
-ifndef purify
-  purify ?=
-endif
+purify ?=
 ifeq ($(purify),0)
   override purify =
 endif # purify
@@ -819,9 +710,7 @@ PURE_CACHE_DIR = $(PURE_CACHE_BASE_DIR)-$(LOGNAME)-$(notdir $(CXX) )
   CPPFLAGS += -DACE_HAS_PURIFY -I$(ACE_PURIFY_DIR)
 endif # purify
 
-ifndef quantify
-  quantify ?=
-endif
+quantify ?=
 ifeq ($(quantify),0)
   override quantify =
 endif # quantify
@@ -843,9 +732,7 @@ ifdef quantify
   endif # sparc
 endif # quantify
 
-ifndef repo
-  repo ?=
-endif
+repo ?=
 ifeq ($(repo),0)
   override repo =
 endif # repo
@@ -859,9 +746,7 @@ ifdef repo
 endif # repo
 
 # If pipes is not set, we default to 0
-ifndef pipes
-  pipes = 0
-endif
+pipes ?= 0
 
 # If pipes is set to 1 then add the compiler flag -pipe. This uses pipe instead
 # of intermediate files. This can be disabled by setting pipes to 0 in the
@@ -871,18 +756,13 @@ ifeq ($(pipes),1)
 endif # pipes
 
 # RMCast is turned on by default
-ifndef rmcast
-  rmcast = 1
-endif
-
+rmcast ?= 1
 ifeq ($(rmcast),1)
   ACE_MAKE_OPTIONS += rmcast
 endif
 
 # If not explicitly is set that we don't have rwho, assume we have it.
-ifndef rwho
-  rwho = 1
-endif
+rwho ?= 1
 
 # If not explicitly is set that we have wfmo, assume we don't have it.
 ifndef wfmo
@@ -893,30 +773,17 @@ endif
 #      Conditional macro definitions
 #----------------------------------------------------------------------------
 
-ifndef PTDIRS
-  PTDIRS ?=
-endif # PTDIRS
-ifndef PRELINK
-  PRELINK ?=
-endif # PRELINK
-ifndef POSTLINK
-  POSTLINK ?=
-endif # POSTLINK
-ifndef PURELINK
-  PURELINK ?=
-endif # PURELINK
-ifndef TEMPLATES_FLAG
-  TEMPLATES_FLAG ?=
-endif # TEMPLATES_FLAG
-ifndef MVCMD
-  MVCMD ?=
-endif # MVCMD
+PTDIRS ?=
+PRELINK ?=
+POSTLINK ?=
+PURELINK ?=
+TEMPLATES_FLAG ?=
+MVCMD ?=
 
 COMPILE.c       = $(CC) $(CFLAGS) $(CPPFLAGS) -c
 COMPILE.cc      = $(CXX) $(CCFLAGS) $(CPPFLAGS) $(PTDIRS) -c
-ifndef RC
-  RC ?=
-endif
+RC ?=
+
 COMPILE.rc      = $(RC)
 COMPILE-NO_DASH_G.cc = `echo $(COMPILE.cc) | sed 's/-g //'`
 # 960905 Marius Kjeldahl <marius@funcom.com>