Bug 1341504 - Don't disable incremental linking when optimizations are turned off. r=glandium

Incremental linking is automatically disabled when -OPT:REF or -OPT:ICF are used.
Seeing that we're disabling optimizations anyway, may as well not use those linker flags as they considerably slow down linking.

MozReview-Commit-ID: 9OXG19uxeI9

--HG--
extra : rebase_source : 4703bc4bb62af3f054ca621be7c1c51fe56cb2f3

config/config.mk

@@ -166,24 +166,20 @@ ifndef MOZ_DEBUG
 # Used for generating an optimized build with debugging symbols.
 # Used in the Windows nightlies to generate symbols for crash reporting.
 ifdef MOZ_DEBUG_SYMBOLS
-ifdef HAVE_64BIT_BUILD
-OS_LDFLAGS += -DEBUG -OPT:REF,ICF
-else
-OS_LDFLAGS += -DEBUG -OPT:REF
-endif
+OS_LDFLAGS += -DEBUG
 endif
 
 #
 # Handle DMD in optimized builds.
 #
 ifdef MOZ_DMD
-ifdef HAVE_64BIT_BUILD
-OS_LDFLAGS = -DEBUG -OPT:REF,ICF
-else
-OS_LDFLAGS = -DEBUG -OPT:REF
-endif
+OS_LDFLAGS = -DEBUG
 endif # MOZ_DMD
 
+ifdef MOZ_OPTIMIZE
+OS_LDFLAGS += -OPT:REF,ICF
+endif # MOZ_OPTIMIZE
+
 endif # MOZ_DEBUG
 
 endif # WINNT && !GNU_CC