diff --git a/make/common/Defs-solaris.gmk b/make/common/Defs-solaris.gmk
index b14b9b2bbdac4d4acc310f5003271de97b11f2cf..b08488f4277bf606c44edb2e105d8c37490c892f 100644
--- a/make/common/Defs-solaris.gmk
+++ b/make/common/Defs-solaris.gmk
@@ -231,18 +231,21 @@ endif
 # optimization flags as used by FASTDEBUG. We also want all the
 # debug info in one place (-xs).
 #
+CFLAGS_COMMON=
+CXXFLAGS_COMMON=
 ifeq ($(ENABLE_FULL_DEBUG_SYMBOLS),1)
   ifeq ($(LIBRARY_SUPPORTS_FULL_DEBUG_SYMBOLS),1)
     ifeq ($(VARIANT), OPT)
-      CC_OPT   = -g  -xs $(CC_OPT/$(FASTDEBUG_OPTIMIZATION_LEVEL))
-      CXX_OPT  = -g0 -xs $(CXX_OPT/$(FASTDEBUG_OPTIMIZATION_LEVEL))
+      OPTIMIZATION_LEVEL = $(FASTDEBUG_OPTIMIZATION_LEVEL)
+      CFLAGS_COMMON += -g  -xs
+      CXXFLAGS_COMMON += -g0 -xs
     endif
     CFLAGS_DEBUG_OPTION    += -xs
     CXXFLAGS_DEBUG_OPTION  += -xs
   endif
 endif
 
-CFLAGS_COMMON   = -L$(OBJDIR)
+CFLAGS_COMMON  += -L$(OBJDIR)
 
 # Do not allow C99 language features like declarations in code etc.
 CFLAGS_COMMON  += -xc99=%none