gbuild: fix GCC_VERSION check

This was intended to check for GCC 4.8, but that would be
GCC_VERSION=408, not 480, so fix the check.  Not sure what GCC 4.9
actually does here, though.

Change-Id: I32e9aafd36ea7fb81aac52f6788c97fc42b5c8e1
Reviewed-on: https://gerrit.libreoffice.org/56381
Tested-by: Jenkins
Reviewed-by: Michael Stahl <Michael.Stahl@cib.de>

solenv/gbuild/platform/com_GCC_defs.mk

@@ -107,7 +107,7 @@ ifeq ($(COM_IS_CLANG),TRUE)
 gb_CXXFLAGS_COMMON += -Wimplicit-fallthrough
 else
 # GCC 4.8, at least, is confused by boost 1.66 optional assignments
-ifeq ($(shell expr '$(GCC_VERSION)' '<' 490),1)
+ifeq ($(shell expr '$(GCC_VERSION)' '<' 409),1)
 gb_CXXFLAGS_COMMON += -Wno-maybe-uninitialized
 endif
 endif