change Makefile to set up latex at start

git-svn-id: http://newslabx.csie.ntu.edu.tw/svn/Ginger@70 5747cdd2-2146-426f-b2b0-0570f90b98ed

trunk/RTCSA_SS/Makefile

@@ -4,6 +4,7 @@
 # The LATEX variable contains the latex command to use, using LATEXFLAGS
 # you can specify additional flags to pass. 
 TEXPATH = /usr/local/texlive/latest/bin/universal-darwin
+TEXPATH = $(dir $(shell which $(LATEX)))
 LATEX = pdflatex
 LATEXFLAGS= -interaction=scrollmode 
 PDFLATEX = pdflatex