diff -r 6a2d73358ff7 -r c760f78e0a53 make/solaris/makefiles/gcc.make
--- a/make/solaris/makefiles/gcc.make	Thu Dec 02 14:00:03 2010 -0500
+++ b/make/solaris/makefiles/gcc.make	Wed Dec 01 15:04:06 2010 +0100
@@ -47,11 +47,14 @@
 
 # check for precompiled headers support
 ifneq "$(shell expr \( $(CC_VER_MAJOR) \> 3 \) \| \( \( $(CC_VER_MAJOR) = 3 \) \& \( $(CC_VER_MINOR) \>= 4 \) \))" "0"
+# Allow the user to turn off precompiled headers from the command line.
+ifneq ($(USE_PRECOMPILED_HEADER),0)
 USE_PRECOMPILED_HEADER=1
 PRECOMPILED_HEADER_DIR=.
 PRECOMPILED_HEADER_SRC=$(GAMMADIR)/src/share/vm/precompiled.hpp
 PRECOMPILED_HEADER=$(PRECOMPILED_HEADER_DIR)/precompiled.hpp.gch
 endif
+endif
 
 
 #------------------------------------------------------------------------
@@ -138,6 +141,11 @@
 DEPFLAGS = -MMD -MP -MF $(DEP_DIR)/$(@:%=%.d)
 endif
 
+# -DDONT_USE_PRECOMPILED_HEADER will exclude all includes in precompiled.hpp.
+ifneq ($(USE_PRECOMPILED_HEADER),1)
+CFLAGS += -DDONT_USE_PRECOMPILED_HEADER
+endif
+
 #------------------------------------------------------------------------
 # Linker flags