configure.ac: revert last modif to set STARPU_GLPK_LDFLAGS

configure.ac

@@ -1016,6 +1016,7 @@ if test x$enable_memory_stats = xyes; then
 fi
 
 AC_CHECK_HEADERS([glpk.h], [AC_DEFINE([STARPU_HAVE_GLPK_H], [1], [Define to 1 if you have the <glpk.h> header file.])])
+STARPU_HAVE_LIBRARY(GLPK, [glpk])
 AC_CHECK_HEADERS([Ayudame.h])
 
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