diff --git a/configure/os/CONFIG.Common.vxWorks-ppc604 b/configure/os/CONFIG.Common.vxWorks-ppc604
index 1b8db3168..e4da21572 100644
--- a/configure/os/CONFIG.Common.vxWorks-ppc604
+++ b/configure/os/CONFIG.Common.vxWorks-ppc604
@@ -16,6 +16,9 @@ ARCH_CLASS = ppc
 
 # Architecture specific build flags
 ARCH_DEP_CPPFLAGS = -DCPU=PPC604
-ARCH_DEP_CFLAGS = -mcpu=604 -mstrict-align -mno-implicit-fp
+ARCH_DEP_CFLAGS_2 = -mcpu=604 -mstrict-align -mno-implicit-fp
+ARCH_DEP_CFLAGS_3 = -mcpu=604 -mstrict-align -mno-implicit-fp
+ARCH_DEP_CFLAGS_4 = -mcpu=604 -mstrict-align -fno-implicit-fp
+ARCH_DEP_CFLAGS = $(ARCH_DEP_CFLAGS_$(VX_GNU_MAJOR_VERSION))
 
 GNU_TARGET = powerpc-wrs-vxworks
diff --git a/configure/os/CONFIG.Common.vxWorksCommon b/configure/os/CONFIG.Common.vxWorksCommon
index f218337d8..fc86e6c8c 100644
--- a/configure/os/CONFIG.Common.vxWorksCommon
+++ b/configure/os/CONFIG.Common.vxWorksCommon
@@ -82,14 +82,19 @@ VXWORKS_MAJOR_VERSION = $(basename $(basename $(VXWORKS_VERSION)))
 
 # These are needed for vxWorks 6.x; the GNU toolset version number
 # is in the path to the compiler tools:
+VX_GNU_VERSION_5.4 = 2.95
+VX_GNU_VERSION_5.5 = 2.96
 VX_GNU_VERSION_6.0 = 3.3.2
 VX_GNU_VERSION_6.1 = 3.3.2
 VX_GNU_VERSION_6.2 = 3.3.2
 VX_GNU_VERSION_6.3 = 3.4.4
 VX_GNU_VERSION_6.4 = 3.4.4
 VX_GNU_VERSION_6.5 = 3.4.4
+VX_GNU_VERSION_6.6 = 4.1.2
 VX_GNU_VERSION = $(VX_GNU_VERSION_$(VXWORKS_VERSION))
 
+VX_GNU_MAJOR_VERSION = $(basename $(basename $(VX_GNU_VERSION)))
+
 #--------------------------------------------------
 # Fix WIND_BASE for vxWorks 6.x on linux
 # NB: We know the value of WIND_HOST_TYPE here, but not VXWORKS_VERSION