Apparently LO patched GNU make 3.82 interprets the semicolon which is
the value of $(gb_CLASSPATHSEP) as a terminator if it occurs while
setting a target local variable; the part of the value that follows the
first semicolon is cut off.
Hence escape the $(gb_CLASSPATHSEP) and $(XCLASSPATH) vars.

Change-Id: I213dba7155f9515e492c20cfff3bef1c4d8269fc