Use fortran 90 compiler and correct flag for C preprocessor.

diff --git a/src/makefiles/Makefile.xlf90_mpi_O2 b/src/makefiles/Makefile.xlf90_mpi_O2
new file mode 100644
index 0000000..abb638b
--- /dev/null
+++ b/src/makefiles/Makefile.xlf90_mpi_O2
@@ -0,0 +1,45 @@
+#-*- mode: makefile -*-
+#-----------------------------------------------------------------------
+#                  IBM Fortran Compiler + MPI
+#-----------------------------------------------------------------------
+#+ This file is part of the AENET package.
+#+
+#+ Copyright (C) 2012-2016 Nongnuch Artrith and Alexander Urban
+#+
+#+ This program is free software: you can redistribute it and/or modify
+#+ it under the terms of the GNU General Public License as published by
+#+ the Free Software Foundation, either version 3 of the License, or
+#+ (at your option) any later version.
+#+
+#+ This program is distributed in the hope that it will be useful, but
+#+ WITHOUT ANY WARRANTY; without even the implied warranty of
+#+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#+ General Public License for more details.
+#+
+#+ You should have received a copy of the GNU General Public License
+#+ along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#-----------------------------------------------------------------------
+# 2015-05-26 Alexander Urban (AU) and Nongnuch Artrith (NA)
+#-----------------------------------------------------------------------
+
+SUFFIX   = xlf90_mpi_O2
+
+FC       = mpif90 -c
+LD       = mpif90
+DEBUG    = # -g -warn all -check bounds
+FCFLAGS  = -compiler xlf90_r -WF,-DPARALLEL -O2 -g -q64 -qarch=pwr7 -qtune=pwr7 $(DEBUG)
+LDFLAGS  = $(DEBUG)
+NUMLIB   = -L$(SCINET_LAPACK_LIB) -q64 -lessl -llapack -lrefblas
+
+CC       = xlc_r -c
+CCFLAGS  =
+
+# linker for C-interoperable library (gcc & gfortran)
+LIBLD    = xlc_r
+LIBFLAGS = -qmkshrobj
+LIBLIB   =
+
+AR       = ar
+ARFLAGS  = -crusv
+
+include ./Makefile.inc